Xen domU problems after updating from 10.3 to 11.1

I had a very good running 10.3 Xen server system with four domU´s: rbovm1…4.

After updating to 11.1 and rebooting the Xen-system I get allways the following error message for each of my existing domU´s located at /xenvm/vmimages/rbovm1…4:

Starting auto Xen domains

rbovm1: Error: domUloader requires specification of bootargs

rbovm2… the same
rbovm3… the same
rbovm4… the same

failed.

I didn´t change anything to the script files and forced Xen to look at /xenvm/vmimages… for the domains.

What´s going wrong. The domU OS is still openSuSE 10.3 for each domain and works as DNS, DHCP, FTP and Webserver very well until I did the update of dom0 to 11.1.

I have backup´s of my virtual machine files, so it won´t be the problem to switch back to 10.3 for dom0. but I would like to run the system with 11.1.

Thanks for hints.