First ML350 G5 is not certified by VMware for 5.5 . Reference Link - http://www.vmware.com/resources/compatibility/detail.php?deviceCategory=server&productid=3532&deviceCategory=server&details=1&keyword=%22ML350%20G5%22&page=1&display_interval=10&sortColumn=Partner&sortOrder=Asc
Secondly looking at the screenshot it looks to be a hardware issue on the host.
Have you run hardware diagnostics on the host lately?