Can´t install MacosXServer 10.6.3 as Guest, under Snow Leopard 10.6.8

[mcmatthew]

Hi,

why i can´t install MacosX Server 10.6.3 as guest, under my Snow Leopard 10.6.8 Host Operating System?
I got the failure message (ID 397) -> The virtual machine can only started with 10.5 or 10.4.

Version:
Build 7.0.14924

I hope anyone can help me.

Best Regards
Matthias