I dont think GTA3 has ever worked yet as it uses palettes and I dont recall us ever finishing it (Raphael is the one to ask).
However, try commenting out the line in directx.c : object->visInfo = glXChooseVisual(object->display, DefaultScreen(object->display), dblBuf);
This has caused problems on some manufacturers device drivers. Its something we need to fix, but there's also numerous other things...
There's no demo for gta3 last time I looked :-(
Jason