Creating snapshots failing

Hi Everyone,

I'm having an issue creating a snapshot of my VMs. Here is the error message I'm getting.

An operation required the virtual machine to quiesce and the virtual machine was unable to continue running.

Cannot open the disk '/vmfs/volumes/51ace766-006cb31c-f239-bcaec5630d13/VM-DIR/VM.vmdk' or one of the snapshot disks it depends on.

The system cannot find the file specified

VMware ESX cannot find the virtual disk "/vmfs/volumes/51ace766-006cb31c-f239-bcaec5630d13/VM-DIR/VM-000001.vmdk". Verify the path is valid and try again.

I am running ESXi 5.1.0, 1065491 using vSphere Client 5.1.0, 786111.

My VM details are

Linux (RH6) 64 bit

4GB mem

1CPU

IDE Hard Disk

When I look at the vm dir, it lists a lot of .vmdk files

example

VM-000001-s001.vmdk, VM-000001-s002.vmdk, VM-000001-s002.vmdk, etc.

I have not been able to find any information on the quiesce error.

Any information would be appreciated.

Thanks,

C. Yang