这是我的XSD文件：http://www.da-ra.de/fileadmin/media/da-ra.de/Technik/4.0/dara.xsd。 我是从https://www.da-ra.de/dara/typo3/typo3?lang=en&ext=en%2Ftechnical-information%2Fdoi-registration%2F获得的。
当我将XSD文件放入XSD验证器（http://www.utilities-online.info/xsdvalidation/#.XOKFnKTgphE）中并检查XSD有效性时，它表示该文件无效。有谁知道那是为什么？鉴于XSD文件来自官方网站，因此应该可以。
来自验证器的错误：
Not valid.
Warning - Line 7, 69: org.xml.sax.SAXParseException; lineNumber: 7; columnNumber: 69; schema_reference.4: Failed to read schema document 'include/dara-resourceType-v4.1.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 12, 69: org.xml.sax.SAXParseException; lineNumber: 12; columnNumber: 69; schema_reference.4: Failed to read schema document 'include/dara-otherTitleType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 17, 70: org.xml.sax.SAXParseException; lineNumber: 17; columnNumber: 70; schema_reference.4: Failed to read schema document 'include/dara-contributorType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 22, 71: org.xml.sax.SAXParseException; lineNumber: 22; columnNumber: 71; schema_reference.4: Failed to read schema document 'include/dara-availabilityType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 27, 69: org.xml.sax.SAXParseException; lineNumber: 27; columnNumber: 69; schema_reference.4: Failed to read schema document 'include/dara-relationType-v4.1.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 32, 62: org.xml.sax.SAXParseException; lineNumber: 32; columnNumber: 62; schema_reference.4: Failed to read schema document 'include/dara-pidType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 37, 70: org.xml.sax.SAXParseException; lineNumber: 37; columnNumber: 70; schema_reference.4: Failed to read schema document 'include/dara-descriptionType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 42, 75: org.xml.sax.SAXParseException; lineNumber: 42; columnNumber: 75; schema_reference.4: Failed to read schema document 'include/dara-identifierSchemaType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 47, 72: org.xml.sax.SAXParseException; lineNumber: 47; columnNumber: 72; schema_reference.4: Failed to read schema document 'include/dara-timeDimensionType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 52, 73: org.xml.sax.SAXParseException; lineNumber: 52; columnNumber: 73; schema_reference.4: Failed to read schema document 'include/dara-collectionModeType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 57, 67: org.xml.sax.SAXParseException; lineNumber: 57; columnNumber: 67; schema_reference.4: Failed to read schema document 'include/dara-documentType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 62, 63: org.xml.sax.SAXParseException; lineNumber: 62; columnNumber: 63; schema_reference.4: Failed to read schema document 'include/dara-unitType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 67, 67: org.xml.sax.SAXParseException; lineNumber: 67; columnNumber: 67; schema_reference.4: Failed to read schema document 'include/dara-rightsCCType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 72, 68: org.xml.sax.SAXParseException; lineNumber: 72; columnNumber: 68; schema_reference.4: Failed to read schema document 'include/dara-languageCodes-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 77, 76: org.xml.sax.SAXParseException; lineNumber: 77; columnNumber: 76; schema_reference.4: Failed to read schema document 'include/dara-resourceLanguageCodes-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 82, 87: org.xml.sax.SAXParseException; lineNumber: 82; columnNumber: 87; schema_reference.4: Failed to read schema document 'include/dara-internalClassificationSchemaType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 87, 82: org.xml.sax.SAXParseException; lineNumber: 87; columnNumber: 82; schema_reference.4: Failed to read schema document 'include/dara-controlledKeywordSchemaType-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Warning - Line 92, 63: org.xml.sax.SAXParseException; lineNumber: 92; columnNumber: 63; schema_reference.4: Failed to read schema document 'include/dara-geoCodes-v4.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
Error - Line 99, 57: org.xml.sax.SAXParseException; lineNumber: 99; columnNumber: 57; src-resolve: Cannot resolve the name 'resourceType' to a(n) 'type definition' component.
Error - Line 482, 65: org.xml.sax.SAXParseException; lineNumber: 482; columnNumber: 65; src-resolve: Cannot resolve the name 'resourceLanguage' to a(n) 'type definition' component.
Error - Line 489, 57: org.xml.sax.SAXParseException; lineNumber: 489; columnNumber: 57; src-resolve: Cannot resolve the name 'metadataLanguage' to a(n) 'type definition' component.
Error - Line 1582, 69: org.xml.sax.SAXParseException; lineNumber: 1582; columnNumber: 69; src-resolve: Cannot resolve the name 'collectionModeType' to a(n) 'type definition' component.
Error - Line 1877, 65: org.xml.sax.SAXParseException; lineNumber: 1877; columnNumber: 65; src-resolve: Cannot resolve the name 'availabilityType' to a(n) 'type definition' component.
Error - Line 2267, 47: org.xml.sax.SAXParseException; lineNumber: 2267; columnNumber: 47; src-resolve: Cannot resolve the name 'pidType' to a(n) 'type definition' component.
Error - Line 207, 63: org.xml.sax.SAXParseException; lineNumber: 207; columnNumber: 63; src-resolve: Cannot resolve the name 'titleType' to a(n) 'type definition' component.
Error - Line 565, 105: org.xml.sax.SAXParseException; lineNumber: 565; columnNumber: 105; src-resolve: Cannot resolve the name 'classificationSchemaType' to a(n) 'type definition' component.
Error - Line 659, 79: org.xml.sax.SAXParseException; lineNumber: 659; columnNumber: 79; src-resolve: Cannot resolve the name 'keywordSchemaType' to a(n) 'type definition' component.
Error - Line 779, 75: org.xml.sax.SAXParseException; lineNumber: 779; columnNumber: 75; src-resolve: Cannot resolve the name 'descriptionType' to a(n) 'type definition' component.
Error - Line 808, 119: org.xml.sax.SAXParseException; lineNumber: 808; columnNumber: 119; src-resolve: Cannot resolve the name 'geographicCoverageControlled' to a(n) 'type definition' component.
Error - Line 1222, 83: org.xml.sax.SAXParseException; lineNumber: 1222; columnNumber: 83; src-resolve: Cannot resolve the name 'timeDimensionType' to a(n) 'type definition' component.
Error - Line 1308, 87: org.xml.sax.SAXParseException; lineNumber: 1308; columnNumber: 87; src-resolve: Cannot resolve the name 'contributorType' to a(n) 'type definition' component.
Error - Line 1352, 87: org.xml.sax.SAXParseException; lineNumber: 1352; columnNumber: 87; src-resolve: Cannot resolve the name 'contributorType' to a(n) 'type definition' component.
Error - Line 2409, 57: org.xml.sax.SAXParseException; lineNumber: 2409; columnNumber: 57; src-resolve: Cannot resolve the name 'unitType' to a(n) 'type definition' component.
Error - Line 1910, 71: org.xml.sax.SAXParseException; lineNumber: 1910; columnNumber: 71; src-resolve: Cannot resolve the name 'licenseType' to a(n) 'type definition' component.
Error - Line 1963, 66: org.xml.sax.SAXParseException; lineNumber: 1963; columnNumber: 66; src-resolve: Cannot resolve the name 'pidType' to a(n) 'type definition' component.
Error - Line 1968, 69: org.xml.sax.SAXParseException; lineNumber: 1968; columnNumber: 69; src-resolve: Cannot resolve the name 'relationType' to a(n) 'type definition' component.
Error - Line 1973, 83: org.xml.sax.SAXParseException; lineNumber: 1973; columnNumber: 83; src-resolve: Cannot resolve the name 'resourceType' to a(n) 'type definition' component.
Error - Line 2051, 83: org.xml.sax.SAXParseException; lineNumber: 2051; columnNumber: 83; src-resolve: Cannot resolve the name 'documentType' to a(n) 'type definition' component.
Error - Line 2398, 81: org.xml.sax.SAXParseException; lineNumber: 2398; columnNumber: 81; src-resolve: Cannot resolve the name 'identifierSchemaType' to a(n) 'type definition' component.