ugh. well, grindstone is one of those three in my entrenchment galaxy folder. there must be some connection here.
probably the galaxy folder of the original is empty or even non-existant. just to be sure, could you go check it. it should be something like:
C:\Programs\Stardock\TotalGaming\Stardock Games\Sins of a Solar Empire\Galaxy
there you should find a good number of maps, significantly more than 3.
not sure what to do if it isn't there or empty. maybe your installation f*ed up. let's see ...
well, I'd make sure the game is otherwise working nicely. if it were really a bad install you'd have to uninstall/ reinstall it. it everything else is ok, then I could zip up my local galaxy files and send them over. could do via email or maybe via rapidshare or sth. long time I used that though.