I guess you're one of the rare ones that can't get ISPConfig3 to work properly.
Well its safe for me to say that I had 100% success every time I installed it (which is about 20 times now) by following these tutorials (mostly just the first one):
http://www.howtoforge.com/perfect-se...er-ispconfig-3
http://www.howtoforge.com/changing-f...config3-server
http://www.howtoforge.com/extending-...ze-ispconfig-3
I hope this helps you, if not, I hope other people will check this out. ^_^