Well, I don't know if you have to do all this to do an upgrade. I think most people are having problems upgrading because they are using Windows 7 (I don't have Vista, but it is probably the same) and in Windows 7 there are two places where you need to erase the vendor.xml file, one is in c:\Program Files (x86)\Common Files\Research In Motion\AppLoader\ and the second one (which I have only seen mentioned once in a forum) is in c:\Users\<username>\AppData\Local\VirtualStore\Pro gram Files (x86)\Common Files\Research In Motion\AppLoader\ (needless to say, replace "<username>" with the username you logged in to when installed the device software).
After that just disconnect your internet connection and use loader.exe (also located in c:\Program Files (x86)\Common Files\Research In Motion\AppLoader\. I did not uninstall anything, did not rebooted the BB or had to quickly run loader while the red LED was on. I even had my BB on the white screen and "reload software error 513" on it. I have done it with both a 9000 and a 8900, with the latest version of Desktop Manager installed (although I only used loader.exe). I hope this helps somebody.
Last edited by mczapata; 05-18-2010 at 10:41 PM..