I'm not familiar with the Sprint version and so others might give you specific advice on the issue.
I can offer some basic advice.
In this order and without changing or shortcutting any steps:
1) Uninstall the BB OS on your PC
2) Uninstall DTMrg on the PC and reboot.
3) Clean up your registry on the PC by deleting references to RIM/BB/DTMgr (may also require a reboot)
4) Download DTMgr and the OS from your provider to make sure you are using the version they support for your BB (Check to be sure the OS on the desktop is the same as on your device)
5) Install DTMgr
7) Install the OS
8) Now, for the first time since reinstalling the software, connect your BB.
9) If you still can't install apps, repeat each step but before you connect the BB, wipe the device.
NOTE: You should always back up your data and your apps before wiping your device.
Good luck....this worked for me. I had the same problem.
Last edited by Roll : 07-11-2008 at 12:54 PM.