This product has expired. Be sure that your host machine's date and time are set correctly.VMWare has a KB article that it is updating with the latest info, and is promising updates by noon PST tomorrow (8/13). In the mean time, there are some suggested workarounds in the VMWare Communities.
There is a more recent version available at the VMware web site: http://www.vmware.com/info?id=4.
Module License Power on failed.
This will totally nail you if you do maintenance on a VM. So if you have ESX in your business, this is very much worth noting.