Tech, how about searching/asking this in Kerio forum since there are specialists?
Jarmo's solution made my day. Disabling 'address resolving' make the GUI stable and working.
The fact system cannot be connected at startup... well, waiting for further updates or I'll change the firewall. Kerio was solved, the new owner should show hability to solve, update, etc. If not, there are other reliable options. For me, the best firewall is still Outpost Pro (without the spyware module).