VMware nos recomienda si utilizamos Composer 2.0 no actualizar a vSphere 4.1 por la sencilla razon que este funciona solo con 64bits y Composer no lo soporta. Segun comentan su web, la nueva version que esta al caer (llevan meses de retraso, todo sea dicho) si lo soportara: VMware View 4.5
"vSphere 4.1 (Including ESX, ESXi, and vCenter Server)
VMware View Composer 2.0.x is not supported in a vSphere vCenter Server 4.1 managed environment as vSphere vCenter Server 4.1 requires a 64 bit operating system and VMware View Composer does not support 64 bit operating systems.
VMware View 4.0.x customers who use View Composer should not upgrade to vSphere vCenter Server 4.1 at this time. Our upcoming VMware View 4.5 will be supported on VMware vSphere 4.1" http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1011292
