Installation Problem

I have made several attempts to install PunBB.

Following the instruction exactly, I'm told to access install.php from the directory the files were uploaded to e.g http://www.mydomain.com/forum/install.php

My root installation is then shown as: e.g. http://www.mydomain.com/forum/upload/  - I'm confused why this should be so when the forum should be just /forum/

After correctly completing the installation and uploading config.php into the root of /forum as detailed in the install page, I am getting "config.php not found or is corrupted".

Should the config file actually be in uload directory? Or what am I doing wrong? I'm very confused.

Thanks for any help