SnapDeploy 2 - only 6 clients

Hi everybody.
The situation:
I've installed SnapDeploy 2.0 on a XP Workstation (PXE, licence-server, console)
The DHCP is an Win2k3 Domain Controller.

I've tried to deploy 17 machines (I selected "all clients" in the console) - but it only worked with six of them. The other 11 rebootet into the PXE (some of them showing strange messages in the console like 1500% done!).
I've tried it a second time with the 11 ones left (changing to unicast as it is suggested in the Acronis FAQ) - but got the same effect: it worked only with six PCs again.
It needed three deployment processes for 17 machines! (And I've 23 more to do - and 23 free licences).

Any ideas or suggestions ?
Thanks.