nightlong is abit tricky on some setups , 15 and 16 bit modes have to be selected on which api u use, and on the mediator it needs some more memory, but a v5500 have 64megs ram so i dont see this as a prob for you.
anyway if you get mono picture, try and open in diffrent resulutions (and diffrent modes) , and if you get a trashy screen do a multitask back to wb and instantly back to the game (sounds weird but it works for me) , then the display is OK here.
only happens like 1 or 2 times while i play..
i have tried nightlong on PIV, CV643d , Bvision , Vodoo3 , voodoo5 ..
for quake 2 , start from a clean shell line and not using last prefs (NOLRU) (not last recently used) then set it up again, then it should work fine, as it have some features that may and may not crash..
enjoy