Hi,
Thank you for posting in Symantec community.
Upgrade of Vmware tools is not necessary but make sure ESXi 4.1 update is installed.
& Upgrade from 3.2.1 to 3.3.2 is not supported.
Upgrade from 3.2.1 to 3.3 or 3.3.1 is supported.
VMware ESXi, VMware ESX, and VMware vSphere 5 is a supported platform for Symantec Encryption Management Server.
Environmental Requirements for Symantec Encryption Management Server (previously PGP Universal Server) clustering
http://www.symantec.com/docs/TECH157115