You don't understand - that DB error is the result of the uninstall. With the mod installed, that table is installed with it. Once you uninstall the mod, the tables go with it as well. When I then try to access my forum for example:
http://www.notworking/forums/, that's wen you get the DB error.
There are a few ways around this -- I could just disable the plugin and ignore it, but that defeats the purpose. I could also probably add the table 'post_thanks_thanked_times' back into the DB and that may patch the problem, but again that's defeating the purpose of an uninstall.