It would have been helpful if you had told us which line was line 26, rather than making me count them.

The error means just what it says : that a variable you are using in an eq comparison has not been initialised, ie it is undefined. Have a look at perldiag for an explanation of this warning.

I am guessing that that variable is $action.

You could change your param sub to always return a defined value. For instance:

   sub param {
       my $key = shift;
       my $value = ....code to get value...;

       return defined $value 
           ? $value 
           : '';
   }
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Update

As blazar pointed out below, param() is from CGI, so you could do the following:

   sub get_defined_param {
       my $value = param(@_);
       return defined $value 
           ? $value
           : '';
   }
[download]

and replace all your call's to param() as follows:

    my $title     =  get_defined_param('title');
    my $request   =  get_defined_param('request');
    my $orderlist =  get_defined_param('orderlist');
    my $remark    =  get_defined_param('remark');
    my $host      =  get_defined_param('host');
    my $date      =  get_defined_param('date');

    my $action    =  get_defined_param('action');

    my $gamefile  =  get_defined_param('gamefile');
    my $gamename  =  get_defined_param('gamename');
    my $gamedesc  =  get_defined_param('gamedesc');
    my $counter   =  get_defined_param('counter');
[download]