Problem with combat/simulator rendering

I just started a full tech game and finished creating all the ship designs that I could possibly think of (I think that puts it around 60), but I want to test them in the simulator before using resources to build them. The regular ship pics show up in the design window just fine, but when I go into the simulator, they disappear, replaced by a random assortment of magenta horizontal lines and race pics (I don't want a ship shaped like a Norak). What's worse, I can't place the ships beforehand, because they don't show up in the combat screen, and when I do actually fight, I can't launch specific units because the game crashes with 'Access violations.' And any lingering graphics problems persist until I close the game, at which point it complains about another Access violation. Really frustrating.

Here are the different messages I keep getting (if anyone can make sense of them):
Access violation at address 00731087 in module 'SE5.exe'. Write of address 0000002B.
Access violation at address 0047AB57 in module 'SE5.exe'. Write of address 0000C028.
Access violation at address 0047B11 in module 'SE5.exe'. Write of address 00000000.
Access violation at address 006F552C in module 'SE5.exe'. Write of address 00000014.
There are probably more, I just don't care to write them all down.

This is occurring on two different computers with different performance characteristics, both running SE5 1.71 with a variation of Balance Mod 1.14a (basically just modified Stellar Manipulation-related tech into a racial trait, so I could decimate all the puny races with my power...fear me little ones...). I'm wondering if anyone else is having this problem with either the 1.71 patch or Balance Mod, or if it might be due to my modifications (although everything I did should have had no effect on the overall graphics rendering), or if it's just some fluke with my particular game file that can't be rectified, and must be recreated (that's a few tens of hours down the drain).