我是Liferay Portal的新手。我的配置是：
我正在学习如何使用Liferay中的服务构建器来构建服务。这样做时，我收到以下错误：
[Console output redirected to
file:D:\workspace\.metadata\.plugins\com.liferay.ide.eclipse.sdk\sdk.log]
Buildfile:
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\portlets\guestbook-portlet\build.xml
[taskdef] Could not load definitions from resource
org/apache/ivy/ant/antlib.xml. It could not be found.
BUILD FAILED
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\portlets\guestbook-portlet\build.xml:5:
The following error occurred while executing this line:
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\portlets\build-common-portlet.xml:5:
The following error occurred while executing this line:
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\build-common-plugin.xml:5:
The following error occurred while executing this line:
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\build-common.xml:57: The following error occurred while executing this line:
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\build-common-ivy.xml:719:
The following error occurred while executing this line:
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\build-common-ivy.xml:166:
The following error occurred while executing this line:
D:\Liferay\liferay-plugins-sdk-7.0-ce-ga1-20160331161017956\liferay-plugins-sdk-7.0\build-common-ivy.xml:193:
Problem: failed to create task or type
antlib:org.apache.ivy.ant:settings Cause: The name is undefined.
Action: Check the spelling. Action: Check that any custom tasks/types
have been declared. Action: Check that any <presetdef>/<macrodef>
declarations have taken place. No types or tasks have been defined in
this namespace yet
This appears to be an antlib declaration. Action: Check that the
implementing library exists in one of:
-D:\eclipse\plugins\org.apache.ant_1.8.3.v20120321-1730\lib
-C:\Users\33329\.ant\lib
-a directory added on the command line with the -lib argument
如果选中，则在build-common-ivy.xml中的以下taskdef中失败：
<taskdef classpathref="ivy.lib.path" resource="org/apache/ivy/ant/antlib.xml" uri="antlib:org.apache.ivy.ant" />
请告知如何解决此问题。