I just got a 7100t from T-Mobile and all has been great so far, except for the IM problem that this great site helped me solve.
I just installed the BB Desktop Manager and when I use the Application Loader, the software doesn't find any system software installed...seems very strange to me. Nothing show up in the area where the apps should be listed. Here's the exact error:
"No system software was found on your handheld. Contact your system administrator or service provider for info on obtaining system software."
BB software is: v126.96.36.199
Desktop Manager is: v188.8.131.52