Any ideas on 'uninitialized value in lenth'?

[Bret Goodfellow]

Here's a simple perl script where I am listing out the contents of a
directory.  When it completes, the following error occurs.  How do I
eliminate this?
 
Use of uninitialized value in length at C:\BegPerl\deldir.pl line 23.
 
Below is the script:
 
#!/usr/bin/perl
# Dsrch1.plx
# use strict ;
use warnings ;
 
$directory = $ARGV[0];     
 
opendir(DIR, $directory) or die "Can't open $directory\n" ;
$direntry = readdir(DIR);
 ($mtime) = stat($direntry);
#######################################################
# read entire directory contents and print out        #
#######################################################
while (length($direntry) > 0) {
 
 print "$direntry - modify date: $mtime\n" ;
 $direntry = readdir(DIR);
}
 
closedir(DIR);