Having a problem conneting to an Oracle 11gr2 RAC

Don't know if anyone has worked with the Oracle RAC environment and
perl.

Using sqlplus, I can do the following

C:\>sqlplus ais_dbo/PASSWORD@edc-dbserver/HCSMDA

SQL*Plus: Release 10.2.0.1.0 - Production on Thu Apr 29 11:55:35 2010

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit
Production
With the Partitioning, Real Application Clusters, Automatic Storage
Management, OLAP,
Data Mining and Real Application Testing options

And then execute queries, updates ...

From ActiveState perl running on a windows 2003 server box with
DBD-Oracle 1.21 and DBI 1.609

C:\>perl -v

This is perl, v5.8.9 built for MSWin32-x86-multi-thread (with 9
registered patches, see perl -V for more detail)

Copyright 1987-2008, Larry Wall

Binary build 825 [288577] provided by ActiveState
http://www.ActiveState.com
Built Dec 14 2008 21:07:41

Perl code follows

#!/usr/bin/perl -I .
require 5.001;
use strict;
use DBI;

MAIN:
{
    print "Started\n";

    my $dbh = DBI->connect("dbi:Oracle:host=edc-dbserver;sid=HCSMDA",
"ais_dbo","PASSWORD", 
                            {RaiseError=>1, PrintError=>0});
	my $sqlstmt = "SELECT COUNT(*) FROM VESSEL_IDENTIFIERS";
	my($no_of_ships) = $dbh->selectrow_array($sqlstmt); 
    print "Got $no_of_ships ships\n"
 }

Executing the above, I get 

Started
DBI connect('host=edc-dbserver;sid=HCSMDA','ais_dbo',...) failed:
ORA-12505: TNS:listener does not currently know of SID given in connect
descriptor (DBD ERROR: OCIServerAttach) at C:\adbtest.pl line 15

I've got a standalone oracle database (11gr1) pointed to by host alias
dbserver.  If I use dbserver above instead of edc-dbserver, the script
works fine.

Also, tnsping gives the following

C:\>tnsping edc-dbserver

TNS Ping Utility for 32-bit Windows: Version 10.2.0.1.0 - Production on
29-APR-2010 12:57:46

Copyright (c) 1997, 2005, Oracle.  All rights reserved.

Used parameter files:
C:\oracle\product\10.2.0\client_1\network\admin\sqlnet.ora

Used HOSTNAME adapter to resolve the alias
Attempting to contact
(DESCRIPTION=(CONNECT_DATA=(SERVICE_NAME=edc-dbserver.nais.org))(ADDRESS
=(PROTOCOL=TCP)(HOST=10.166.135.110)(PORT=1521))(ADDRESS=(PROTOCOL=TCP)(
HOST=10.166.135.112)(PORT=1521)))
OK (0 msec)

Any help would be greatly appreciated.

E. Scott Stricker
Senior Software Engineer
Northrop Grumman - Information Systems - C2SD 
MailStop 4S02
2340 Dulles Corner Blvd.
Herndon, VA 20171
703-561-3671
703-713-1601 (fax)