Steven Zahm@ James
It is very unlikely that the installation of cMap caused the rich text editor to not function as nearly all of its code run exclusively on the sites frontend. Did you by chance install or update another plugin in WP around the same time of noticing that the editor was broke? The issue you describe is more likely being caused by a plugin/theme conflict where the plugin/theme is not limiting its javascripts to their own admin pages. At least that is my experience when this pops up once in a great while.
I would first suggest running thru the plugin conflict check:
Before that, you if you load the page in Chrome, hit the F12 key and click the Console tab. It list javascript errors that occurred on the page. One of those errors is likely the source of the issue. If mouseover the filename in the far right of the error, the file path will be displayed. This file path can possibly offer a clue on which exact plugin may be causing the conflict.
Hope this helps, let me know what you learn.