Perl/Tk System Function Error

[perl.j]

I am making an "all-in-one calculator" (I guess). Here is my code (I know I do not have all subroutines defined, I'm still working on this as you can see):

use 5.12.4;
use warnings;
use Tk;

##### Create MainWindow #####
my $button_menu = new MainWindow;
#############################

##### MainWindow Buttons#####
my $calculator_button = $button_menu->Button(-text=>"Calculator",
                                         -width=>10,
                         -relief=> 'raised',
                             -command=>\&open_calculator)->pack();

my $formulas_button = $button_menu->Button(-text=>"Formulas",
                                       -width=>10,
                       -relief=> 'raised',
                       -command=>\&open_formulas)->pack();

my $lcf_button = $button_menu->Button(-text=>"Find LCF",
                                  -width=>10,
                      -relief=> 'raised',
                      -command=>\&open_lcf)->pack();

my $gcf_button = $button_menu->Button(-text=>"Find GCF",
                                  -width=>10,
                      -relief=> 'raised',
                      -command=>\&open_gcf)->pack();
#############################
sub open_calculator{
    system(qq{start "C:\\Windows\\system32\\calc.exe"});
}

MainLoop;

Why does the system function not open the Windows calculator? Also, is there any source code I could use to make a basic calculator in Tk?

Thanks!