Now when I turned the poweron to my home xenserver (a dc7900 HP) I was happy to see the xenserver console. Turned on xencenter client on my laptop and connected to the xenserver. Now I thought let's fireup my DC01 and EX01. The DC01 went on after a few issues had to do a reboot from the console but the EX01 emediatly said the following error "this vm needs storage that cannot be seen from that host". Strange thing is my storage (a local harddisk) ran fine cause I could also see my console and connect to the xenserver from the console. After investigating I saw that my cifs iso library was disconnected and after doing a repair suddenly my vm's were able to turn on. Why a VM won't turn on if it cannot find a virtuel iso attached is a riddle cause the vm does not need the iso to run a server?

The solution is plain and simple. disconnect a iso on your vm and you will be able to turn the vm on. If not then you have a bigger problem that I expirienced.