Yeah, I think it's an issue with the user's code. I created a simpler hello world in the same directory and it works: http://abonae.heliohost.org/cgi-bin/test.cgi.
I don't know Perl, so I'm not sure what's wrong. The user's code:
#!/usr/bin/perl -w
use CGI qw(:standard);
print header;
print <<EOF;
<html>
<head>
<title>hello, world</title>
</head>
<body>
<h1>hello world</h1>
</body>
</html>
EOF