Download the client again, but first delete erasedpkzcache from your C drive.
If this doesn't work, open up erasedpkzcache and find the exe, and try and play it from their, if this still doesn't work, uninstall your java, and reinstall (again).
If the problem still continues to persist, restart your computer, if all else fails, get on teamviewer with Dylan and he should be able to help.
If NOTHING works, then just settle for the webclient.