1) I've installed the eDonkey command line client and I am trying to get the GUI working. First of all, the install:
[root@localhost edonkeyfileshare]# rpm -i ./ed2k-gtk-gui-0.6.0-2.i386.rpm
warning: user tim does not exist - using root
warning: group tim does not exist - using root

I don't know what the warnings mean. To make sure it is installed, I tryed to install it again and found out it is definitely installed. Now I try to run it:

[root@localhost edonkeyfileshare]# ./ed2k-gtk-gui-0.6.0-2
bash: ./ed2k-gtk-gui-0.6.0-2: No such file or directory
[root@localhost edonkeyfileshare]# ed2k-gtk-gui-0.6.0-2
bash: ed2k-gtk-gui-0.6.0-2: command not found

What do I have to do to get it going?

2) My second question is whether a chosen port number is important. In the command client I got the following message:

> Loading shared files...
ERROR: can't listen on port 4662.
Port is probably in use.
Change port by typing: 'port ####' at the prompt.
Upload Queue not loaded
Done loading shared files.

So I changed it to port 3662. Is that OK or is there certain ports I shouldn't use?

Never used edonkey.Only heard about everywhere that it sucks.You could try lmule or mldonkey.There is a lot of info and FAQ's at http://www.mldonkey.org