When trying to uninstall a custom module from our 6.2.1 CE application, the following error message appears at the top of the window:
Specified directory '' for zip file 'cache/upload/upgrades/module/thenameofourmodule.zip' extraction does not exist.

I tried all suggestions in the three following related threads - but unfortunately to no avail:

http://www.sugarcrm.com/forums/f6/sp...tus-0-a-73798/
I cannot install modules in SugarCRM
http://www.sugarcrm.com/forums/f115/...t-exist-39863/

How can I solve this problem?