Policy change hangs Fortigate 30D - Firmware: FGT30D-5.00-build292

Hi

I have an issue with my Fortigate 30D appliance in that if I make a change to the policy it hangs the device and I have to force a restart  to the system. Any active users on the device is also stuck until the device is restarted.  

After restarting the device the new policy has been applied.

I have also had the same problem when making a change to the SSL-VPN portal

Simon