Have you deleted the contents of DCBackup or the folder fully (in itself I mean)? Even if you are doing a clean-up, you should still keep the folder. You can delete its contents but that's it. If you have deleted the folder fully, I would advise creating a new folder in Documents/Electronic Arts/The Sims 3, titled "DCBackup".
Anywho, if you haven't deleted the folder itself and only its contents, then can you please remember if you have deleted the ccmerged.package file too? There have been rumours going around that deleting this file makes store items function incorrectly. Some people are having issues if they delete that particular file and others do not, so this is something questionable, but it could turn out to be true. The file [ccmerged.package] contains information about moodlets and interactions associated with downloadable premium content items from the store so this is why people think that deleting this file, especially after the release of recent premium items, such as the deep fryer and ice cream maker, will cause the items to not work as supposed.
Ok, enough about the cause and on to the fix of your problem. First and foremost, I would suggest deleting your four cache files (all found in the Electronic Arts/The Sims 3 folder, in .package format; socialCache.package is not important). If that doesn't help, my next suggestion would be to remove the .sims3pack for this particular item (or, if you want, the whole goth set) and downloading and reinstalling it again. A fresh new .sims3pack should be able to work properly.