What happened???

I did the OS 10.4.10 upgrade on my Xserve (which is acting as my Contacts and Event server) and once I restarted, the Contact Server came back online immediately but the Event server had crashed. I tried reloading it and even importing a backup data set, but no go. Every time, after importing, the status changes to "Down" and there's no visible cure. I've even tried opening up my firewall and changing ports... nothing.