NT 4 Print Server errors

[HSESupport]

We have set up one of our NT4 servers as a print server.
80% of the time there is no problems with users printing.

However during times of peak printing users recieve "Error, Retry" and also sometimes "Access denied" messages. This is during peak printing times, while system resources are not anywhere peak usage.
The spool folder has been shared to "Everyone", and SP has been applied.

Any possible reasons?

 

[TheLad]

How many printers have you got on your server (I presume it is one server) ? "It's true, its damn true!"

 

[HSESupport]

Upwards on 56 Hp Jetdirect printers, being printed to via LPR.