CIS causing failure by going down into Hibernate / Ruhezustand

This is a failure I found since more or less one year.
Yesterday I again tried to install Comodo on my laptop (Lenovo X61, Vista Business) and testet the functions of CIS.

The problem is the following:

The time CIS 8or in earlier times Comodo Firewall) is installed, the computer can’t go down to hibernation mode - which is VERY important for people on the run with there laptop !

There is no error displayed - it just hangs.

The Suspend to ram mode, which did not work either in former times, now works fine. I can go down to suspend and wake up again.

What could be the reasons for that ?
I would realy like to use COmodo and I think it is one of the best firewalls on the market - but this behaviour makes it impossible to use !

I would be very pleased if someone could help me on that.