[Users] Upgrade problem.

Hi! I upgraded from oVirt 3.1.16 to 3.1.19 under CentOS 6.3 (yum update). The thing is now oVirt is not starting. The web interfaces says: Service Temporarily Unavailable, the VMs don't starts (the box is configured as all-in-one) I have 2 VMs on production. What I can do ? Thanks.-