This morning/afternoon I contacted one of our customers that was having the Invalid Pointer issue and asked if I could connect remotely to his Desktop.
He allowed me access. Once I was in I ran a few tests to find out exactly where in the code the issue was happening. The exception was thrown after trying to create an instance of the BlackBerry Device Manager COM object which lets me enumerate all attached BlackBerry devices attached over USB. This told me that the COM object was not registered in the system properly.
To fix it I did the following:
1. Disconnect your phone from the PC.
2. Download the BlackBerry USB and Modem Drivers from http://www.tetherberry.com/downloads/Drivers.msi
3. Run that installer and choose remove. If it asks you to reboot, do so.
4. Uninstall TetherBerry on your PC.
5. Delete the folder at C:\Program Files\Common Files\Research In Motion\USB Drivers.
6. Delete the folder at C:\Program Files\TetherBerry if it exists
7. Run the installer downloaded in 2 to install the USB drivers.
8. Install TetherBerry.
9. Start TetherBerry.
10. You should now see the message to connect your phone to the PC which means it is no longer getting the Invalid Pointer Error.
11. Plug your phone in and start the TetherBerry application on the phone.
12. If your APN settings are correct, you should now be able to surf the web.
Hope this helps