As long as you've got -w and diagnostics you might as well use strict and put them to good use. Also declare your variables with my so typos will be apparent. When that is done the only error left is this enigmatic line:

die "$!";
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which should just be exit so it won't try to print the empty $doc and get that nasty uninitialized value warning. Try this:

 #!/usr/bin/perl -w

 use strict; # added
 use diagnostics;
 use CGI::Carp qw(fatalsToBrowser);
 use LWP::Simple;

 my$doc;
 my$theURL = 'http://www.theredkitchen.net/';

 print "Content-type: text/html\n\n";
 print "The script has successfully started up.\n\n<BR><BR>";
 
 unless($doc=get($theURL)){
     print "can't get the URL";
     exit; # added
     }
 print $doc;
 exit;
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This code is tested and works. If it doesn't work for you the problem may lie elsewhere...