This is most likely due to 2gb virtual memory address limit of a standard 32bit program (max available memory address space for 32bit Os'es is 4gb which is split in 2gb/2gb for user/os). most likely indicates a memory leak. Might alleviate this problem on a 64 bit os by adding /largeadressaware flag to the game exe file (google for how to) this allows program to use full 4gb address space available to it (since, under 64bit os, os's address space is placed WAY beyond 4gb mark) but ... if its a memory leak it will only postpone the crash a bit.
