I got this error when i migrate liferay 6.2 to liferay 7 with build tool

[Chandrasekhar J]

[Console output redirected to file:E:\Liferay 6.2 _ ATS plugin Upgrade\.metadata\.plugins\com.liferay.ide.sdk.core\sdk.log]

Buildfile: E:\Liferay 6.2 _ ATS plugin\plugins\portlets\chat-portlet\build.xml

CLASSPATH element E:\Liferay 6.2 _ ATS plugin\plugins\.ivy\ivy-2.4.0.LIFERAY-PATCHED-1-SNAPSHOT.jar is not a JAR.

  [taskdef] Could not load definitions from resource org/apache/ivy/ant/antlib.xml. It could not be found.

BUILD FAILED

E:\Liferay 6.2 _ ATS plugin\plugins\portlets\chat-portlet\build.xml:5: The following error occurred while executing this line:

E:\Liferay 6.2 _ ATS plugin\plugins\portlets\build-common-portlet.xml:5: The following error occurred while executing this line:

E:\Liferay 6.2 _ ATS plugin\plugins\build-common-plugin.xml:5: The following error occurred while executing this line:

E:\Liferay 6.2 _ ATS plugin\plugins\build-common.xml:57: The following error occurred while executing this line:

E:\Liferay 6.2 _ ATS plugin\plugins\build-common-ivy.xml:570: The following error occurred while executing this line:

E:\Liferay 6.2 _ ATS plugin\plugins\build-common-ivy.xml:173: The following error occurred while executing this line:

E:\Liferay 6.2 _ ATS plugin\plugins\build-common-ivy.xml:188: 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:

        -ANT_HOME\lib

        -the IDE Ant configuration dialogs

Total time: 1 second