Don`t really know a lot about virtual memory, but I`ve googled and copied this.
Feelin' Mighty Low (on Memory)
When all of your computer's real physical memory (RAM) is in use, Windows will try to create virtual memory by grabbing a chunk of hard drive space and treating it like real memory. Your software can't tell the difference between real and virtual memory, but you might because virtual memory access is much slower, due to the hard drive activity it requires.
If you encounter the low virtual memory error message, then you have used the maximum amount of real plus virtual memory that is supported on your system. Sometimes programs that crash or ones that are poorly designed will not return their working memory space to the operating system when they're done using it. Other programs that need a large amount of memory to run may fail because Windows cannot "see" the available memory. In most cases, a shutdown and restart will resolve this problem.
It also suggests that you may need to install more ram memory.
http://askbobrankin.com/low_virtual_memory.htm l