set-up and configuration

Hello,
So here is my problem, I created a multi-site installation of Drupal using a single source tree with 50+ sub-sites using symlinks for each. The problem I have is if I try to create a page alias on a sub-site that is the same as another symlink sub-site directory Drupal will not display the page. Instead Drupal will validate the URL as the first sub-site's home page.
Here is an example

1) I have a default site at:
www.example.com

2) I have two sub-sites
www.example.com/math
www.example.com/arts

If on the math sub-site I attempt to create a page using pathauto like so:

Hello

We are School (www.schooldigital.co.uk) - a small Drupal specialist digital agency. Occasionally we require additional development resources to help us complete projects for clients.

In this instance we are looking for a Drupal developer to work with us on a short (2-day) project to provide Drupal theming and basic site configuration. (Drupal 5)