I felt compelled to downvote this one, which is very very rare for me. Since it's so unusual, I also felt compelled to explain myself. There is no mention in the post or the code about error checking. It simply assumes that the attempt to open the Word file is successful. What happens when it doesn't? You get an error about undefined values.

How do you make sure that you don't get these mysterious errors?

my $doc = $word->Documents->Open($oldfile) ||
  die("Unable to open '$oldfile': $!\n");
[download]

That's all. Just tell the program to choke and report an error if it can't get the file for some reason.

In retrospect, downvoting may have been an overreaction on my part. Still, this is one of my pet peeves, since it's generally one of the first errors we meet, and often the most common. I've become intimately familiar with that one :-)

I just realized that I was using the same sig for nearly three years.