And this is a DateTime solution:

#!/usr/bin/perl -l
use DateTime;
use DateTime::Duration;

my $date = DateTime->new(
  year      =>    2006,
  month     =>      12,
  day       =>      31,
  locale    => 'en_US',
);

my $duration = DateTime::Duration->new(
  months        =>          1,
  end_of_month  => 'preserve',
);

for ( 1..12 ) {
  $date->add( $duration );  # One month more
  print $date->mdy('/');    # And show it
}
[download]

use DateTime;

my $date = DateTime->last_day_of_month( year => 2006, month => 12 );
print $date->add( months => 1, end_of_month => 'preserve' )->mdy('/') 
+foreach 1..12;
[download]