Problem with ant.

More specifically add the following in the beginning of your classpath:

%ANT_HOME%\lib\ant.jar
 %ANT_HOME%\lib\ant-nodeps.jar
 %ANT_HOME%\lib\ant-launcher.jar

I had the same problem ?and I added these three and it worked.

I got the idea from an IntelliJ thread:

http://support.jetbrains.com/kb/entry.jspa?externalID=59&categoryID=27