Your problems are several.
The first thing that a CGI script should send to the browser is a content type, followed by two newlines, eg: "Content-Type: text/html\n\n".
When none is specified, IE defaults to 'text/html', whilst Mozilla defaults to 'text/plain'.
Secondly, Mozilla is dead and buried, you should really be testing with
Firefox. As an extra bonus, there's a heap of extremely useful web development tools for it.
Thirdly, CGI has been dead and buried for several decades. For Perl web development you'll want to look at
mod_perl, and while you are at it, look at a templating
engine, or
two. I'll leave it to others to recommend various HTML-embedded scripting languages, as I personally dislike them immensly.
Lastly, it's 'Perl', not 'PERL' - stupid, I know, but it's the first thing you'll be told (in liue of a helpful answer) at any
Perl related forum.