I attempted to install a Mercurial VCS plugin into Intellij8. Now the IDE won't start, throwing the exception described in the attached file. I have searched for where this plugin file is installed so I can remove it, but to no avail. The IDE is so badly crippled that I can neither edit source files or open Preferences to remove the plugin. The plugin was installed from Preferences originally.
How can I repair this situation? I have tried uninstalling the IDE and reinstalling, but somehow bits are left behind in the uninstall that are retained in a reinstall, preserving the problem.