Do not plug in your BB untill after you have installed the OS to the computer and deleted the vendor.xml. Here are the instructions from the sticky.
Instructions for installing on ANY carrier's 8320:
1. Make sure you have Desktop Manager 4.2 SP2 or higher installed. If you need it here's a link for Desktop Manager: https://www.blackberry.com/Downloads...93E4F3BB068C22
2. Download the above file to the PC then install it to the PC by running the file you downloaded.
3. Locate the vendor.xml file and delete it. It's located in c:\program files\common files\research in motion\apploader
4. Plug in BB and Open Desktop Manager. You should be prompted to upgrade.
The process takes about 45 minutes to an hour depending on how much data you have to backup and restore during the process. Once it's done loading the new OS it will reboot (it may do this twice during the entire process.) You will see a white screen with an hourglass for up to 45 minutes at a time while the DM says "waiting for initialization."
If you end up with a white screen with small icons and the number 507, simply connect to DM again and run application loader again and it should load the OS to the device