I had some problems starting images from vmware server, on a new esx 3i server and went out to find a solution.
First off, the disk needs to be converted as it does not have the same format. use the following command and it will make a CLONE (its safe to do on the original disk image)
vmkfstools -i nfsvol/source.vmdk vmfsvol/dest.vmdk
after this is done, you schould be able to create a new machine, and attatch the disk. (if its not converted the infrastructure manager will deny accepting the file and give an error message).