You've obviously got "use strict" in your program (which is a good habit to get into) so you need to predeclare[1] all of your variables.

foreach my $k (keys(%LogHash)) {
  print LOGFILE $k, ",", $LogHash{$k}, "\n";
}
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Oh, but there's no need to make that print statement so complex.

foreach my $k (keys(%LogHash)) {
  print LOGFILE "$k, $LogHash{$k}\n";
}
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[1] Or fully qualify their names, but let's not get into that :)