Cannot take snapshot - causing RedHat guest to hang

Hi,

I have a RedHat 6.6 VM and whenever I try to take a snapshot (Manually or from a backup, in this case Symantec BackupExec 2014), the vm becomes unresponsive and eventually crashes the webserver running on it.

One error message I receive from within vCenter Server 5.5 is:

An error occurred while taking a snapshot: msg.snapshot.error-QUIESCINGERROR.

An error occurred while saving the snapshot: msg.snapshot.error-QUIESCINGERROR.

I am running Oracle Webserver 7 on this RHEL 6.6 VM.

vCenter Server 5.5.0

ESXi 5.5

the VM is on VM version 10

Any help would be appreciated.

thanks,

Rob