Can't call method "read" without a package or object reference at...

[Bing D. <Bi...@ci...>]

The following code piece gave the following error.

===============================
#!/usr/sbin/perl

use Net::LDAP::LDIF;

$ldif_file = "/var/md/dsa/master/dump/mailusers.dump";

$ldif = Net::LDAP::LDIF->new("$ldif_file","r");

while ( $entry = $ldif->read() ) {
$entry->dump;
}

$ldif->done();
==============================

Can't call method "read" without a package or object reference at
./for-keith-ph
.pl line 19.

Acctually, most part of the above code was from 'perldoc
Net::LDAP::LDIF'.  Can anybody tell me what I did wrong?

Thanks,

Bing