Knowledge Tree & Blank page on login & logout.

I've been working on implemeting a drupal site for an intranet at work I've managed to install fine using xubuntu, apache2, mysql & php5.

So far I have manged to set up Active Directory authentication and integrated gallery and knowledge tree.

I have now run into an issue that I found lots of similar forum posts relating to the blank page, however none of the solutions seemed to work so I did some testing and it turns out it is related to knowledge tree.

When I installed knowledge tree I had a problem with getting the session names to match and followed the instructions in http://drupal.org/node/193257 and set the $base_url in settings.php (sites/default) to $base_url = 'http://intranet' and this then worked fine.

Since then I have been getting a blank page problem, when I login or logout I get a blank page, if I refresh the page I then get the correct page back. I do not need to repeat the login or logout, this is the main drupal login or logout not the knowlege tree login/logout.

I have looked in both the drupal log and the Apache log (/var/log/apache2/error.log) and there are no errors showing.

If I comment the $base_url out then I don't get the blank page error but I do get the knowledge tree session error.

Apache has been restarted between trying each option and a couple of full machine restarts have taken place as well.

I don't know PHP well enough to write some code but would possible be able to tweak something to fit my set up.

Any thoughts?

Regards

Ticktock