Virgin mobile unlocked 9790 update won't download

I have an unlocked 9790 on Virgin mobile. I was able to update it to 7.1 bundle 1647 successfully. DM shows another 7.1 bundle 2257 available but it won't install. I get a "problem downoading check internet..." message. It zips to 100% download just before the previous message. I suspect that it is RIM telling me about the update and Virgin mobile saying no? Clarification would be appreciated. Thanks again for any and all help.
Allan.

I wonder if the new version if an official release from Virgin. If not, you could delete the vendor.xml file and then perform the install.

No sign of the .xml file anywhere.

Its in you hidden files ;)
You can try to start the upgrade directly from the directory where the os is installed on your pc.
Make sure to make a backup first!