You should probably log back in when you post a follow-up.

Anyway, no, it's not valid. Try changing all the commas to dots:

   my $dateTime = $hour.":".$min,":".$sec," ".$mday."/".$mon+1."/".$ye
+ar+1900."";
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Or you can change $dateTime to @dateTime, and put the whole RHS in parenthesis:

   my @dateTime = ($hour,":",$min,":",$sec," ",$mday,"/",$mon+1,"/",$y
+ear+1900,"");
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Of course, doing that changes how you use it as well. I'm guessing you want the first one. Note that you may also just find it easier to use sprintf:

  my $dateTime = sprintf "%02d:%02d:%02d %02d/%02d/%d",
      $hour, $min, $sec,
      $mday, $mon+1, $year+1900;
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PS - I'm not sure why you have that ending empty string - you should be able to get rid of it.