ESXi 4.1 / Mediawiki 1.17 jumpbox

As often as three times a day, this jumpbox freezes and vmware reports that it's using 100% CPU. At that point, I can't SSH or reach the admin interface (on port 3000). My only option is to power cycle the guest.

I just installed the ESXi vmware tools, but the problem happened again.

how can I trouble shoot this ?