Just want to round off this topic with a summary. Starting with again thanking the Lazarus and FPC teams for the fantastic job they have done and are doing!
Here follows the solution to my initial question. "How to run Lazarus on a Centos 5 system?"
Preparation:
Be sure to uninstall both any previous Lazarus and any previous FPC before following the instruction below.
rpm -e lazarus
rpm -e fpc
1. FPC 2.6.0 can be installed on Centos 5, but I found no RPM's for i386.
Solution: Use fpc-2.6.0.i386-linux.tar which can be downloaded from FPC's site.
There is a binary.i386-linux.tar included. When you unpack it you find an install.sh which executes and installs fpc-2.6.0
NOTE: The RPM's provided on the Lazarus site, ex: fpc-2.6.0-2.fc17.i686.rpm, can not be used on CentOS 5.
The reason is that they require epel6 which is not compatible with CentOS 5.
2. After installing FPC 2.6.0 the Lazarus RPM lazarus-1.0.4-0.i386.rpm on the Lazarus site can be used.
It can not be installed with yum as it specifies dependencies wich require files non-compatible to CentOS 5.
It can be installed using rpm: rpm -i --nodeps lazarus-1.0.4-0.i386.rpm
It installs perfectly, without any problems.
3. Before running Lazarus
If you had a previous installation of Lazarus you might want to get rid of your old configuration which can be found in your home-directory.
If you run lazarus as root this is what you can do:
Log in as root in a terminal.
Remove the .lazarus directory by rm -rf .lazarus
You are now ready for a fresh start and as already said...
It runs perfectly.
/Kamau