This is a long shot, but I thought I'd give it a try. I'm encountering a problem in the mission Saint Mark's Bistro - when I get to the bistro, the floors are... missing. The dude greeting CJ immediately falls down when you see him in the cutscene (his line plays fine, followed by CJ's line). And when you regain control CJ falls down as well. After a long fall you land in what looks like untextured water, with all the mobsters you were suppose to shoot dead. And my options are pretty much to die (and spawn in Venturas hospital) or load a previous save.
SO, any suggestions? I have like 1 mod that involved messing with gta3.img, one that replaces most of the weapons with different models - no mods relating to maps or the Liberty City section... And unfortunately, I didn't keep the original gta3.img (thought I did, but can't find it). Restarting or reloading the game had no effect.