VirtualBox 4.2.1 on a Snow leopard Host does not start

[Ida]

Hi
I'm new to this Forum, I have searched it for possible fixes to my problem.
When I dubble click on VirtualBox in the programs menu, Vb starts up shortly and then terminates immidiately
Have tried to reinstall vb, but that didn't solve the issue.
I have attached some logs to clarify, maybe you can see what it wrong.
I have a windows 8 as a guest system and that is the only vm created so far.

[Ida]

upgraded to vb 4.2.4 still can't open vb, so removed vms from virtualbox vm folder, then vb starts. but if I create new vm and tries to start it I get this error:
Cannot open a session to the virtual machine
Failed to load VMMR0.r0
VERR_SYS_NON SYS Group

Retur kode:
NS_ERROR_FAILURE (0x80004005)
Komponent:
Console
Kort:
IConsole {db7ab4ca-2a3f-4183-9243-c1208da92392}