导出数据库时出现这个奇怪的错误
这是错误报告，
连接到：Oracle Database 11g企业版11.1.0.6.0版 - 生产 使用分区，OLAP，数据挖掘和实际应用程序测试选项
在WE8MSWIN1252字符集和AL16UTF16 NCHAR字符集中完成导出
About to export specified users ...
. exporting pre-schema procedural objects and actions
. exporting foreign function library names for user WELTESADMIN
. exporting PUBLIC type synonyms
. exporting private type synonyms
. exporting object type definitions for user WELTESADMIN
About to export WELTESADMIN's objects ...
. exporting database links
. exporting sequence numbers
. exporting cluster definitions
. about to export WELTESADMIN's tables via Conventional Path ...
EXP-00008: ORACLE error 904 encountered
ORA-00904: "POLTYP": invalid identifier
EXP-00000: Export terminated unsuccessfully
我已授予执行者DBA访问权限，这就是发生的事情。请帮帮我......