Re: Access is denied. (Win32 error 0x5) in Networker 8.2
If the affected clients have Anti Virus software installed, then ensure the Anti Virus the correct rules and exceptions in place to allow the NetWorker software to do it's work.
If the affected hosts do have Anti Virus software as suspected. Then, as a test, try temporarily disabling the Anti Virus, reboot the machine, & try again a Full backup. If it succeeds then you will know the correct rules need to be put in place.
The "Access is denied" suggests to me some other application has a lock on the files (Usually Anti Virus software)...