Hello!
I was trying to install the zenphoto CMS.. but there is a big problem with it!

I've succesfully uploaded all of the files to my FTP server.
I've changed CHMOD's to gallery and cache folders (777), I've renamed the zp-config.php.source to zp-config.php
When I launch the page (http://www.prohosting.vizz.pl) the installation starts.
But when I'm trying to refresh the page - the error occurs.

Please help!
What should I do, when the "lib-gd.php" problem shows?

It would probably help if you tell us exactly what error you get. If I visit your site I see a Gallery installation page....