my %widgets = ();

... # your loops

my $id = "f" . $j . $c; # Create identifier
my $awidget = $frame->Text(-height => 6,
                                -background => 'white', 
                                -width => 10)
                        ->pack(-side => 'left');
die "widget failed $id" if ! defined($awidget);
$widgets{$id} = $awidget;

... # closing the loops