You don't need to do the editing in the cache folders.
As stated before: simply delete the files (except index.html).

Some servers don't allow executing php files outside the root directory or have a special reserved directory for it (some times called personal or private). Check php info or the hosters documentation to know the status on your server.
Moving the xoops_data and xoops_lib has to be in sync with the edited definitions in /mainfile.php.
Try also to erase your cache files.