Exchange 2003 / 2007 Routing Loop Problem

I have a Windows 2003 Domain/Forest with Exchange 2003.  I preped the domain/forest for Exchange 2007 and
installed it on a new server.  I have not started using the 07 server yet but did it did set up the connector
between the 03 and 07 exchange servers.

I notice in the Application event log that we cannot send to certain domains (maybe a half dozen).  It gives this error:

A non-delivery report with a status code of 5.3.5 was generated for recipient rfc822;name@domain.com (Message-ID <Bunch
of numbers here@2003MailServer>).  
Causes: A looping condition was detected. (The server is configured to route mail back to itself). If you have multiple
SMTP Virtual Servers configured on your Exchange server, make sure they are defined by a unique incoming port and that
the outgoing SMTP port configuration is valid to avoid looping between local virtual servers.    
Solution: Check the configuration of the virtual serverÆs connectors for loops and ensure each virtual server is
defined by a unique incoming port.

Why is it that we can send mail to several places but these others return an error 5.3.5?
One article said... "This is where we say you MUST "disable" Linkstate.  Well, technically, you're not going to
disable it.  You're going to suppress the possibility for any connectors to be marked down.  You'll do this by
setting the SuppressStateChanges registry key that is talked about in the Exchange 2003 Routing and Transport Guide.  
This will ensure that legacy versions of Exchange also will only use least cost routing, and there will then be no
chances for loops to occur."...and i did this before I installed the 07 server but i still get this routing loop error.

Should I set up a new connector on Exchane 2007 and call it 'Internet' and have it send mail to the outside?  Or
should I set that up on the Exchange 2003 server?  Will this solve the problem???