Installing Python 2.3.5 - get "need administrator access" to install error.....

[insideview at gmail.com]

Hi there - when attempting to install Python 2.3.5, I receive the
following message -- "You do not have access to make the required
system configuration modifications." Please rerun this installation
from an administrators account. I am running Windows XP in
administrator mode, and have installed versions 4 & 5 with no problems
today.  What could be hanging this older versions installation up?