I download the latest handheld version of 4.2.0.71. I currently have 4.2.0.64. I ran the setup file and then loaded my Desktop Manager. When I plug my BB in, I don't get prompted to upgrade.
I must be missing something. When I re-run the setup file, I get prompted to repair the install.
If you rerun the setup file you'll need to delete the vendor.xml again. Be sure you delete only "vendor.xml" If you delete anything else you'll have problems. It is located in c:\program files\common files\research in motion\apploader.