F8 xen: error starting longhorn

[vger]

Hi,

i did install and run longhorn(RC0) under F8 for quite a while without
problems. 
yesterday i did stop longhorn, patch all dom's and restart the server.
( i am not aware of any xen related patches)

wenn i try to start longhorn now, i get  the message
-------
[root at control1 ~]# virsh start longhorn1
libvir: Xen Daemon error : POST operation failed: (xend.err 'int
argument required')
error: Failed to start domain longhorn1
-------

virsh define works without error message. Btw. its all 64Bit
installation

what to do ?

ds