Your basic problem is in the delfiles routine: the unlink function takes a path name (or a list of path names) not a file handle:

sub delfiles {
  my $count = unlink @files;
  print "number of files deleted: $count\n";
}
[download]

or you could just delete them one at a time using a loop:

sub delfiles {
  for my $path (@files) {
    unlink $file;
  }
}
[download]

which allows you to do something special if the file can't be deleted.

There are other issues with your script, but since this smells like a homework problem, it's probably best if you first attempt to figure those out on your own.