User forwarding an Address Book distribution list from her contact list getting exchange error

• Open Outlook.
• Click on Address Book.
• Go to her contact list.
• Open up a distribution list she created.
• Click on Forward Group and forward as an Outlook Contact
• Selects an internal email address and sends the email.

What happens next is she gets a bounceback message saying the following:

<<
Delivery has failed to these recipients or groups:

EmailAddress

You can't send a message on behalf of this user unless you have permission to do so...

Diagnostic Information for administrators:

Generating Server:

emailaddress@ourdomain.org

#MSEXCH:MSExchangeIS:/DC=ORG/DC-OURDOMAIN/DC=AD:OURSERVER[578:0X000004DC:0x0000001D]#SMTP#
>>

Now
I was curious if it would do this with all of her distributions lists
so I picked a different one and forwarded it in the EXACT same manner
and the second one works fine.

What gives?  Is it possible what is email addresses in the distribution list would cause this strange result?

Thanks,

Greg