Deleting or moving amounts to the same thing, with your operating system.
I would consider fixing the appending thing - your folder has (7) on the end, which may be causing issues. I'm not a programmer, obviously, but I'd suggest correcting that. I don't think it's a good thing to have on there, and it shouldn't be necessary.
Try removing the folder manually under Categories in WP Filebase. That should solve your problem!