I bet you haven't deleted the vendor.xml file have you....
Anyway....do not worry...I'll help you revive your phone easily.....
1) Download BBSAK
= ultrashare.NET - Simple Free File Hosting
2) Connect your BB via the USB
3) Run BBSAK then hit enter when prompted for a password (leave password field blank if you have no password)
4) When BBSAK Loads, click on Wipe OS and wait a few seconds till you get the confirmation that it has been done.
5) Navigate to c:\program files\common files\Research in Motion\AppLoader
6) Delete the file vendor.xml
if it exists
7) Run the apploader again and enjoy :D