How did you take the VMware snapshot?
If you take it using the VI / vSphere client, then it will not quiesce the guest file systems (which SMVI does when it takes a VMware snapshot).
So if a snapshot via the client worked fine, but an SMVI created VMware snapshot caused a timeout, then that suggests to me that there was a problem during the quiesce process.
Have you got the VMware tools VSS components installed inside the VM?