Q: Error 8012 - Pimp my  Keyborad

Hello there, Julio M.

The following Knowledge Base article refers to how to delete Apps from iTunes:

How to delete content you've downloaded from the iTunes Store, App Store, iBooks Store, or Mac App Store

http://support.apple.com/kb/HT5772

For Apps:

Mac or PC

Before you delete, find out if you'll be able to download the app you deleted again (it depends on where you live).

1. Launch iTunes.
2. From the Library pop-up menu, choose Apps.
3. Click the app you want to delete.
4. Press the Delete on your keyboard.

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.