Danke nach Frankfurt!

There are a few bugs in your code, though. I changed the if to a while loop and fixed a few other problems:

    while ($str =~ /searchword/g) {
        my $loc = tell($fh) - length($str) + pos($str);
        print "Found a match starting after $loc.\n";
    }
[download]

Update: That doesn't quite work either... it finds too many occurrences...