Are you getting error code 67 when you try to share the Sprint Vision network on your phone with your computer (via USB or Bluetooth?) Here is the fix that actually works (tested on HTC Snap).
1) Download and install CE Registry Editor at http://ceregeditor.mdsoft.pl/ceregedit_setup.exe
2) Connect your phone to your computer via USB.
3) Run CE Registry Editor. In the top menu, click Connection -> Connect.
4) Navigate to the key "HKEY_LOCAL_MACHINE\Comm\InternetSharing\Settings"
5) The key "ForceCellConnection" should be set to "Phone as Modem". That is bad. Right click on the key, click "edit", and change the value to "Sprint PCS" (no quotes).
6) Click OK.
7) On the top menu, select File -> Save.
This should allow you to tether your HTC devices to your computer (like I said, tested on HTC Snap)