1) You can not install Upgrade 5 Beta 3 over Upgrade 5 Beta 2.
You have to Install Upgrade 5 Beta 3 from Patch 4.1.
2) You must have Directx 9.0b installed (run dxdiag to find out what version you have installed).
3) You must have the LATEST drivers from Nvidia's website installed.
4) Make sure than when you have DBPro reinstalled from Patch 4.1 that you upgrade to Upgrade 5 Beta 3.
5) Dbpro the language can be installed with Windows 98 and Windows ME, but it works best on Windows XP.
6) If none of this works, uninstall your DBPro completely (don't forget to back up your projects before you do this). Then reinstall from CD and reinstall the upgrade 5 non beta patch.
Dark Basic Pro -- The luxury for game programmers everywhere