I don't have an answer (sorry, my LWP is working fine and it's 5.69). But what have you done to track it down? If the debug process seems unweildy to you, check out Effective Perl Programming (we need an id short cut to this). Especially the chapter on Debugging

-derby

update: Okay, off the soapbox. What does the url look like? Is it malformed? What protocols does your LWP support ($ua->protocols_allowed). Does that match-up with the url you're trying to GET? Check out the LWP::UserAgent docs for error 500. Can you retrieve the url outside of perl (by a browser or another offline retrieval tool like GET or wget or curl)?