I should be able to get the internet through my USB activesync connection right! wrong not matter how I tried I could not achieve this simple task until I found this message on the Resco forums, after applying the registry fix It worked..
We have experienced problems with Windows Mobile 5.0 devices and MS ActiveSync 4.20. It is not possible to use the Internet connection via ActiveSync to certain desktop computers - connection to desktop seems working correctly but Pocket Internet Explorer is showing error message 0x80072f78 each time trying to go to any web page.
Here is the solution: Open Registry Editor on your desktop (Start/Run and type "regedit") and locate the key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows CE Services. Right-click on the value list and choose New/DWORD value. Type the name "AllowLSP" and leave the value zero. Disconnect and connect your device and Pocket Internet Explorer (and all other applications) will start working.