Thank you for the message Falko,
Renaming the file and running httpd -t did not help to solve the problem, it did however to find out that Apache was not able to find virtualHosts (No Virtual Hosts). This was however strange, because the line from ISPConfig for the VHosts_ispconfig file was in the Apache Config file.
A closer look to the file, brought out that this directive is twice in place: One time through ISPConfig and one time through the installation of AWStats from the link http://jnsc.de/ispconfig.php
Furthermore I found out more duplicate entries. By removing them everything went fine and I could even install a lot of packages and plugins for ISPConfig.
I am now taking a closer look to the framework, which will be my next task to use it through PHP in our sites
It is getting exciting
I would like only to know how can I make ISPConfig accessible through the internet without giving using the address www.mydomain.com:81
. My web Sites are running on port 80 and ISPConfig is running on port 81 on the same server. Is it possible to access the Control Panel through the respective Site?
I hope this post can help others!