Found it had already been answered, Sorry for not looking corectly, Admins can delete this post. Found the answre, thanks to Tio289, in the ISPconfig forum. I did this to get installed. I had this problem too. I changed the part that finds the Debian version in lib/install.lib.php, line 73, into Changed the "5.0 : to 5.0.1 if(trim(file_get_contents('/etc/debian_version')) == '5.0.1' || trim(file_get_contents('/etc/debian_version')) == 'lenny/sid') {