After I got a black screen (from which I could only reset the PC), I used runitgame.bat outside of GameEx over and over again over a dozen times, and the game started up fine every time.
I noticed one time that as GameEx was launching the game, it played the game start sound (from Galaga?) and then that sound started stuttering before things appeared to lock up.
Also, I tried forcing MAME to use GDI, and when I did, it worked fine from GameEx every time. However, this is not acceptable for a variety of reasons, primarily because of the lack of hlsl.
So this leads me to ask if there is a way to delay MAME's startup a couple of seconds while GameEx closes its d3d windows? In case there is some kind of fluke with the timing?