Virtual Memory is the sum of RAM and Page File.
When getting a warning like this it meant you don't have enough memory to store the temporary data. There's two solutions. Either install aditional RAM, or simply increase the page file. The page file is just to compensate the small amount of RAM and will store temporary data on the hard disk, so it is extremely slow. Increasing the amount of RAM is much faster, but it costs money, increasing the page file doesn't.
There's no noticable performance difference in increasing the page file.
TheMajorMMX - Intel P200 MMX @ 225Mhz - V-Tech (PcPartner) Baby-AT mb w/ Intel Triton TX chipset - Nvidia Riva TNT2 M64 w/ 16MB - 256MB M-Tec SDRAM - Still running.....