CMS Beeing logged out from admincp while editing certain settings.
 

I have a problem with admincp.

I can manga mostly of the settings, but if i manage the usergroup settings, ecpecially the usergroup manager. When i try to save my changes/actions i get logged out and must punch my password again.
Also i try to login 3-4 and it directs me to login again.

When logged in again the usergroup setting has not been changed.

I am logged in with Admin account.

What to do ?