I can just (barely!) get 4 Vickies in a scene with 256Mb, so I would guess you are on the edge with 2 and 128Mb. You can't allocate memory on a PC, only Macs have that problem (!) but you can try messing around with your virtual memory, set it to manual and try different settings, and perhaps pic a partition that isn't to fragmented. It is in the Sytem control panel if memory (!) serves.