running out of ram IS ONE of the causes of minidumps, other causes are errors on the entity files, mesh errors, even missing textures have been known to cause minidumps.
it would help to know exactly which mods in which sequence, the video card driver version, and approximate time from start of game to dump.
also have you tried playing the same mods in the dev.exe? it is a bit better at identifying the cause of errors.
harpo