Norton 360 AutoProtect Slows down software program

I have installed Norton 360 onto a clients computers.  They have a NAS Drive attached to a peer to peer newtwork.

The NAS drive has installed their main accounting software system.  The program is installed on the NAS drive not on the local hard drive.  After we installed NOrton 360 then tried to start the accounting system the software slowed right down.  If we disable Auto Protect the software speeds back up to what it was prior to Norton being installed and another software system was on there.

Can anyone explain to me why Auto Protect in Norton 360 would slow the operation of a software system down so much when it is installed on a NAS drive on the local network??

 

I have input firewall exclusions, for the NAS Drive IP Address and als of rthe software exe files that sit on the NAS drive but no change.  The issues seems to be with AutoProtect and not the Firewall!