A module that should not exist ... It helps to uninstall a module and to remove any residue.
So in the uninstallation of Basic Cart (simple shop) you still find remnants. If you then would consider to activate Basic Cart agian, you get an error.
One can solve this problem using the Easy install module. (Actually Easy install should be named Easy uninstall ... )You see the tab 'Purge Configuations'.
Select the module that has already been uninstalled.
Select all the remains ...
and remove them.
Now you've done a clean uninstall. If necessary you can now activate your module on again.
The module also provides the ability to do all the purge at uninstallation immediately. Recommended...