Starting Calendar service hangs server

Hi.

I have been using wikis on 10.8.2 for a few month now and wanted to add a calendar function. runing the server app and flicking the on switch to turn it on causes the server to be come unresponsive.

• Mouse goes very jerky and cant click anything
• i cant ping the mac from another machine (can before hang)
• wiki no longer responds

i have to hard power off/on. upon boot and running the server app the calendar service is set back to off. i dont see anything in the logs at all.

any ideas?