|I don't think you should have to change that key value from the default. Where did you read this?|
When you say 'network printer' do you mean print servers or printers attached to workstations or servers? (I can see where there might be a problem if they were on servers).
If they are printers connected to workstations, have you tried some basic diagnosis like pinging or accessing a shared dir, etc, on those workstations, or trying to print remotely when logged on as an admin?