I'm not sure whether this is a Linux issue or a Samba issue. For some reason, you seem to have a preference for cups, as opposed to lpr printing. Ok, go with the flow. Using multi port print servers, such as HP500x, ports other than 1 cannot be reached. That is all print jobs come out at port 1, if at all. After installing lpr and switching the Smb.conf to bsd, and modifying the printcap, all works well.
cups can connect to any port if you configure it correctly but anyway - thius is not a Samba issue, if you really think you found a cups problem you should report it at www.cups.org