The warning message refers to variables, but I would say the error in your code is having hard-coded print statements to define your web page.

The best solution would be to have the page layout in an external file, and to substitute data values into parrticular places using HTML::Template, or Template::Toolkit, or another such templating module.

If for some reason it's not appropriate to use an external file, investigate the HTML formatting routines in CGI.pm.