1. Uninstall any previous OS you may have installed.
2. Install the OS to your PC.
3. If you have a Windows PC, change your folders option to show hidden files/folders
4. Then go to: C:\Program Files\Common Files\Research In Motion\AppLoader and delete the vendor file.
5. IF you happen to have Windows 64 bit, go here as well: C:\Users\*your user name*\AppData\Roaming\Research In Motion\BlackBerry\Loader XML andd elete that vendor file as well.
*You need to delete the vendor file(s) whenever you are using an OS that is not from your carrier. A simple search of your c: drive should pull these 2 vendors up as well, but you must have enabled show hidden files/folders.
6. Open up Desktop Manager and check to see if there is an updated OS and install.
or
7. Open up Loader in your PC: C:\Program Files\Common Files\Research In Motion\AppLoader
I would highly recommend uninstalling SocialFeeds prior to this. You can re-install it during the installation process.