Hello, From a general internet search, I found the following web page with a description of the plugin: http://pds-geosciences.wu...o/CAT721_release.txt The first thing that I should mention is that we do not support third party plugins for our software because they have not been developed or tested by us at Exelis. Your best bet would be to get in touch with the developers of the plugin to see what they may have to say. Apart from that, I would recommend removing all files associated with the plugin and work backwards though the installation process that you followed. If that does not make ENVI+IDL work, and the developers of the plugin don't have any advice for you, then the next step would probably be to remove ENVI+IDL and then reinstall ENVI to see if that fixes the problem.