One more question, how do I delete the vendor.xml file?
After the OS is downloaded, you need to click on the installer, which is actually what you downloaded. After the OS is installed to your PC, go to C:/Program Files/Common Files/Research in Motion/Apploader then look all the way at the bottom for the vendor.xml file and delete it.
Since you are there, after deleting the vendor.xml file, you can start your upgrade by clicking on the Loader.exe file in the same Apploader folder. This will bring up Desktop Manager's Apploader utility and start your upgrade.
Elizabeth, it's been a few since you posted, so I'm assuming you are on the edge of your seat watching the fascinating (and sometimes scary) endless cycles of reboots and seemingly endless hour glassing on your Curve's display.
Even if it seems to be stuck and not making any progress, do not unplug your BB until you get a confirmation message that the operation is complete, or you get some kind of error message.