i do get the explicit package name error.

What I meant with my previous post is the following:

{   # this bracket introduces a lexical scope

    my $count;  # $count declared as a lexical outside the sub

    sub add_button {
        #add button entries
        my $addframe = $frm_name4->Frame(
                -background=>'yellow',
                -relief=>'groove',
                -borderwidth=>5)
            ->pack(-side=>'top',
                    -fill =>'x');

        my $addtxtcount =  $addframe->Text(
                -width=>1,
                -height=>1)
            ->pack(-side=>'left',
                    -anchor =>'nw');                   #


            my $addtxtexpense =  $addframe->Text(
                    -width=>8,
                    -height=>1)
            ->pack(-side=>'left',
                    -anchor =>'nw',
                    -padx=>5);

        my $addtxtcost =  $addframe->Text(
                -width=>8,
                -height=>1)
            -> pack(-side=>'left',
                    -anchor =>'nw',
                    -padx=>10);

        chomp(my $expense = $expenseentry->get());
        $expenseentry -> delete('0', 'end');
        $addtxtexpense->insert('end',$expense);

        #cost posting
        chomp(my $cost = $costentry->get());
        $costentry-> delete('0','end');
        $addtxtcost->insert('end',$cost);       
        #countig posting
        $count ++;
        $addtxtcount->insert('end',$count);
        #calculate balance
        my @totalbalance = 0;
        push(@totalbalance,$cost);
        foreach( @totalbalance) {
            my $total += $_;

            ##write new balance
            $balancetxt->delete('1.0','end');
            $balancetxt->insert('end',$total);

            #open  WRITEFILE , ">>$time.txt" or die "write error\n";
            #print WRITEFILE ("$count) $expense          $cost \n");
            #close WRITEFILE;

        }
    }
}
[download]

That way you have the $count declared outside the subroutine, and it will not be re-initialized inside the sub at every pass.

Maybe the subroutine is totally wrong!

That might well be, but it's up to you to find out...

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}