I'm not sure I get what it is you're trying to do... However, to the extent that I think I know, try the following:

for (1 .. int(scalar @data / 5)) {
   my $certification = shift(@data);
   my $number        = shift(@data);
   my $month         = $mon[$number - 1];
   my $day           = shift(@data);
   my $year          = shift(@data);
   my $mo_yr         = shift(@data);

   print "Certification is $certification on $month $day $year <p\/><H
+R>\n";
}
[download]

I'm guessing that there is a better way of doing this, but without knowing what the rest of the script is doing...

--greg