/howard$: ls test
Apr15                  May15                  testpm.dat
EDI204_blah            testing_all_Oct14.tar  testpm2.pl
/howard$: perl -d -e 1
...
main::(-e:1):   1
  DB<1> $path='/howard/test/'
  DB<2> opendir(DH,$path)
  DB<3> @files=readdir(DH)
  DB<4> closedir(DH)
  DB<5> x @files
0  '.'
1  '..'
2  'Apr15'
3  'EDI204_blah'
4  'May15'
5  'testing_all_Oct14.tar'
6  'testpm.dat'
7  'testpm2.pl'
  DB<6> open $fh,'<',$files[6] or die $!
No such file or directory at (eval 22)[/home/edi/perl/5.8.8/lib/5.8.8/
+perl5db.pl:628] line 2.
  DB<7> open $fh,'<',$path . $file or die $!
  DB<8> close $fh
  DB<9> @fglob = glob($path . "*")
  DB<10> x @fglob
0  '/howard/test/Apr15'
1  '/howard/test/EDI204_blah'
2  '/howard/test/May15'
3  '/howard/test/testing_all_Oct14.tar'
4  '/howard/test/testpm.dat'
5  '/howard/test/testpm2.pl'
  DB<11> open $fh,'<',$fglob[6] or die $!
  DB<12>
[download]

A couple things to note:

1. readdir returned the . and .. links, glob did not
2. Both returned both directories and files (Apr15 and May15 are directories).
   You will want to test to make sure $file is a file before you try to open it.
3. readdir returned file name only, glob the whole path. That's why open $fh,'<',$files[6] failed.
   I needed to append the path before opening the file.