I think you might be missing Apache IVY library. Download it from here - apache ivy Copy the jar in your ant lib directory.
For example (change version numbers as appropriate):
- Download and install Ant (e.g.,
C:\Apps\Tools\apache-ant-1.9.7).
- Download and extract Ivy (e.g.,
C:\Users\UserName\Downloads\apache-ivy-2.4.0)
- Copy
C:\Users\UserName\Downloads\apache-ivy-2.4.0\ivy-2.4.0.jar into C:\Apps\Tools\apache-ant-1.9.7\lib.
Ant is configured to use Ivy.