Virtual Memory Error on Win XP

Am running a new Win XP (home) system.
P4 Proc,2.4GHz w/533MHz front side bus/512K L2 Cache. 256MB DDR SDRAM at 266MHz, 40GB Ultra ATA/100. This is not a networked computer.
The 3rd day of using this new computer I received the following error message:

Windows Virtual Memory Minimum too low. Your system is low on Virtual Memory. Windows is increasing the size of your virtual memory paging file. During this process, memory requests for some apps may be denied.

Why did this occurand how does it affect me?
Any help would be greatly appreciated…
lmcdonald@wickett-craig.com