Your question about which user runs a Ghost Console task has already been answered by Nigel Bree in your earlier thread here:
https://www-secure.symantec.com/connect/forums/custom-robocopy-batch-file-backup-user-profile
However, the access denied message may be due to the antivirus program on the target system as psexec is one of the pstools that is often recognised as malware by virus checkers (eg Sophos).
I suggest you check the A/V logs and the event log on the target machine in case they have more pertinent information, or try with the A/V uninstalled on a test machine.
If this is not the issue, then try setting the destination of your robocopy command to a local folder on the hard disk as a test. This will establish whether the issue is over network access or not.