Normally thee are no problems, but there is one catch. If you have multiple versions of the same device OS only the newest one can be installed to a BlackBerry.
Also it is possible to have the incorrect OS get installed. Yesterday, I had all the following versions installed on my PC.
Cingular 7100g 4.0.2.56
Cingular 7290 4.0.2.49
Cingular 8700c 4.1.0.194
Nextel 7100i 4.1.0.136
Nextel 7520 4.1.0.273
Sprint 7250 4.1.0.241
T-Mobile 7100t 4.0.2.49
T-Mobile 7290 4.0.2.49
Verizon 7130e 4.1.0.268
Verizon 7250 4.0.0.204
Verizon 7250 4.0.2.41
I was trying to install Verizon 7250 4.0.2.41 on a Verizon device so that is could use EVDO and tethering. My first attempt actually installed Sprint 7250 4.1.0.241. The Vendor.xml file should have prevented this, but didnt. I dont need to delete the vendor.xml file because I am only trying to install the correct carriers OS on any given device. I had to uninstall Sprint 7250 4.1.0.241 before the proper OS would install onto the Verizon device.
The hardest part is trying to figure out which install to remove as that all look basically the same in Add/Remove Programs. I have resorted to editing the registry so that the Carrier and device model are displayed when 'Click here for support information" button is pressed .