I did a "Perfect Server" Ubuntu 8.04, then followed the ISPC3 installation procedure.
The perfect server setup is for ISPConfig 2 and not 3. The perfect server setup is completely incompatible with ISPConfig 3. It is not possible to install ISPConfig 3 on this setup, you will ahve to format the server and reinstall it by following the ispconfig 3 installation instructions. The ispconfig 3 installation instructions can be found inside the ispconfig3 tar.gz file.