More info please? It works for me:

use strict;
use warnings;

use Win32::OLE ();

my $ex = Win32::OLE->new('Excel.Application')
or die("Unable to open Excel object\n");

foreach my $key (keys(%$ex)) {
   print($key, "\n");

   # Application
   # Creator
   # Parent
   # ActiveCell
   # ActiveChart
   # ActivePrinter
   # ...
}
[download]

Or if you want to to iterate over a collection returned by a OLE object, use the in function provided by Win32::OLE.