Hi! I haven't used the latest edition of VA. However, the prior versions did not seem to like compressed archives much. Is this ZIP file compressed? If so, you may want to do one of the following.
1) Unzip the contents into a directory and add the latter to your Workspace classpath.
2) Unzip the contents, archive the constituent files into a jar file and add the latter to the Workspace classpath.
Hope this helps! Feel free to ask if something's not too clear.
Cheers!