I can save you 8 valuable characters :)

$ver = $ver +1;
   |
   |
   V
$ver++;
[download]

Update:

        if ($command =~ /<VER NUMBER> /)
        {
            $command =~ s/<VER NUMBER>/$ver/;
        }
[download]

is logically equivalent to:

        $command =~ s/<VER NUMBER> /$ver /;
[download]