[CentOS] Slow printing to HP jetdirect from cups

I've googled for this and poked around linuxprinting.org, but couldn't find anything helpful.

I have a CentOS 5 server with an HP LaserJet 4 attached via JetDirect with the hplip driver. The problem is that when I have multiple print jobs in the queue, there is a delay of about 15 seconds between each job. This gets very annoying when there are 10-15 one-page jobs in the queue. "lpstat -t" shows me errors like this:

recoverable: Network host 'seashell' is busy; will retry in 15 seconds...

This worked fine previously with the same setup on an old RedHat release (Either RH7 or RH9, I don't remember which). The problem appeared after I rebuilt the server with CentOS 5.

Any ideas would be appreciated.