This can be quite complex to troubleshoot. Usually this is an Apache crash of the webserver.
At first I recommend that you make sure you have the appropriate hardware and memory ressources on your server as per the release notes:
http://www.cisco.com/en/US/products/ps6305/prod_release_notes_list.html
Then, it's important to find out what other applications are running on your server and, if you are in a vmware environment, make sure you have the appropriate ressources for your ESX host.
You can post your logs.zip from WCS and I can check what I can find in there.