If I understand well, all you have to do once you have installed PSE11, is to convert the old catalog. In the catalog manager, you choose 'convert' and navigate to your old catalog. That creates a new catalog in the new PSE11 format (without changing the old one) and keeps the original location and properties of your pictures files.
Thanks for your help, but that didn't fully help with my problem
My Computer A (stationary) has the catalogue and the pictures. Now I want to install PSE on computer B (server) which has a copy of the catalogue and the pictures.
If I install and convert the catalogue on computer B, I assume it will look for the location on computer A instead of B.
That is my problem, if I was able to describe it better.