Posted December 15, 2011
AstralWanderer: If you replace the hgm.exe file (back it up first, just in case) with the 1.07 no-cd version (later versions just patch the file, so quite likely won't work with GOG's version) from GameCopyWorld's Haegemonia page then this problem should go away.
When I tried this the game started giving me error messages about an invalid CD-key when I tried to play skirmish or multiplayer - the campaign still seems to work, though.