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messala: Hi.

I'm running Windows 8.1 64bits and I got the same "abnormal" exception. To me, the Windows buit-in "run compatibility troubleshooter" under the properties of nwmain.exe file fixed it.
Myz: Elaborating for those who might be stuck:

It works for me if i set "windows xp (service pack 2)" under compatibility tab for "nwmain.exe and nwloader.exe (not sure if the second one is necessary though).

Then open the game by double-clicking on the "nwmain.exe" instead of using the "play" button on GOG Galaxy (for those using that, like me)
If the proper compatibility settings are chosen, Windows xp sp 2, then Galaxy should run it.