With help from several great and knowledgeable folks on this list, my 
status code 54 error has been eliminated.

It turns out that the person responsible for the Solaris backup server had 
placed "files, dns" in the nsswitch.conf file,
and my (failing) client was the only address included in the /etc/hosts 
file. I removed it from there, and
things started working again. Odd, because the IP address was correct....

Now, I'm off to find out why this "change" happened, but that's another 
story ;)

Thanks again to everyone who helped!

-Rich McGee
CSU San Bernardino