I've never used LWP::Simple, so there may be something else going on, but one thing I think is, you need to print a header, to tell the browser to expect html. The easiest way to do this is

use CGI qw(:standard);
print header;
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(It may seem like a sledgehammer to crack a nut, using a big module like CGI.pm just to print out a little old header, but... it does get the nut cracked. I used to get really bored typing print "content-type:text/html\n\n";.)

One other thing - you say all you get in the way of an error message is internal server error? Then CGI:Carp is your friend. Add these lines:

use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
print header;
warningsToBrowser(1);
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... then it'll send you some more informative stuff, delivered straight to your browser (or View Source to see the warnings).

§ George Sherston