Is $files a relative path? I think stat needs the full path to the file. Try something like this:

#!/usr/bin/perl -wT
use strict;

my $dir = "/var/www/html/file";

my @files;
opendir (FILE,$dir) || die "'$dir' $!";
@files = grep {-f "$dir/$_"} readdir (FILE);
closedir (FILE) || die $!;


foreach my $file (sort(@files)) {
  my $mtime = (stat("$dir/$file"))[9];
  print "$mtime => $file\n";
};
[download]

-Blake