Unfortunately a few things went wrong with this installation.
With the help of this page I could help a few problems. Unfortunately not all.
My GD seems to be not working accordingly anymore.
When a huge search for a few days on the internet I noticed the PHP need to be compiled with GD by ./configure --with-gd
Unfortunately the command ./configure was not known on my machine and "locate configure" did not succees in finding the shell bash configure..

As I'm a noob on linux and for the moment only could handle myself with guidelines/faqs and forums I'm kinda desperate at the moment and hope some can help me with this issue or guide me to a link where I can fix my problem.
I'm working on a Fedore Core 3 machine and running Plesk 7.5.4 on it.