How does a texture loaded?

Hi, currently I'm desperately trying to find the source of a major memory leak. In my current project, at every 20-30 game, it would crash and the game would hog up to 1,5 gigs of mem and 9 gigs of virtual mem. At every mission it would leak at least 50-100 megs if the mission was ended. After much effort with the memory leak detector resources here and the dumpTextureStats() function, I noticed that there were some NULL / undetermined texture holds and even when the mission was ended, the textures from the previous mission (eg. the DIF's diffuse, the player's diffuse, etc) is not freed. Is this normal? I reckon it's not, but, hey, what do I know anyway. I only barely know the surface of the engine's source code. Any idea on how to solve this problem I have? Thanks.