If you have upgraded a large number of Virtual Machines from ESX 2.x to ESX 3 you may find it easier to do a batch upgrade of VMware tools than to do them individually.The batch upgrade command can be found on the VirtualCenter server in the "c:\program files\vmware\vmware virtualcenter 2.0" directory and the syntax is :

vmware-vmupgrade.exe -u <user> -p <passwd> -n "cluster-name/VM-name"

for example

vmware-vmupgrade.exe -u administrator -p password -n "mybigdatacenter/quickvm"