[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.

-- 
Bowie