Errors in another server want to go to MWS/navigator.html

I've got a problem here with another web server, but the problem does relate to MWS.

When I first tried to run a server, I installed MWS. As I was testing it I noticed that page not found errors went to a special folder named MWS and a file named navigator.html. I know that this is a virtual folder and file and that they do not exist on my PC in that format. Ultimately I did not stay using MWS, but settled on another server program because MWS just was not working for me.

However MWS seems to have altered my system permanently. Even after removing the folder, errors in my server are still being directed to a non-existant file navigator.html in a non-existant folder MWS. They still appear as if MWs was still there.

I need to know how to remove these remaining traces of MWS and set my server to use it's own error pages instead of MWS.

Can anyone please help?