How to install XP on VM Ware?

Whenever I am trying to install any OS on VM Ware Ver. 7.1 I am getting one pop message "Not Enough physical memeory is available to power on the virtual machine with its configured settings. To fix the ptoblem incerase the amoumt of physical memory  for all virtual machines to 455 MB  or adjust  the additional memory settings to allow more virtual machines memory to be swapped."

How should I remove this error to install the OS to VM Ware. Please help me out.

Thank