You have your answer already, but I'd like to point something else out that may bite you later on. You should really consider removing the use CGI qw/:standard/; line from your code. That imports a whole slew of functions into your namespace, including one called 'param'. CGI::Application already has a 'param' method, and you are replacing it with CGI.pm's param method. If you start depending on CGI::Application's param method in the future, bad things will start happening, cause it will invoke the wrong function when you call $self->param.

Unless you actually want to use the CGI.pm functions in your code, you shouldn't need to import anything. CGI::Application already gives you a CGI.pm query object to get your parameters. If you really want to use the html helper functions, think of fully qualifying them instead (CGI::h1, CGI::popup_menu, etc...). Or if you really want those functions imported, try to just import the functions that you need (use CGI qw/:html/)