SMTP outbound fails Event logs show event 3200, 3267 and 9158

Hello,

I have an Exchange 2003 front end server and 3 Exchange 2003 back end servers.  The Front end server sits in the DMZ and is the only server allowed to send smtp outbound.  SMTP outbound works fine for any Outlook client.  But applications cannot sent an smtp message out and I also can't telnet smtp out.  When I try to telnet, the message says that the mail is
queued for delivery, but it never gets delivered.  I can't see it in the queue. When I tried message tracking, it looks like the mail is delivered to the front end server but never goes anywhere.  I have multiple error messages on the front end server:

Event Type:      Information
Event Source:      MSExchangeMTA
Event Category:      Field Engineering
Event ID:      3200
Date:            6/27/2005
Time:            5:45:21 PM
User:            N/A
Computer:      CRP0001
Description:
A timer started with the timeout value set to 10. [XAPI GATEWAY 18 138] (6)

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Event Type:      Information
Event Source:      MSExchangeMTA
Event Category:      Interface
Event ID:      3267
Date:            6/27/2005
Time:            5:45:21 PM
User:            N/A
Computer:      CRP0001
Description:
A MT_WAIT message was received from the /DC=COM/DC=MYDOMAIN/CN=CONFIGURATION/CN=SERVICES/CN=MICROSOFT EXCHANGE/CN=MyDOmain/CN=CONNECTIONS/CN=SMTP (CRP0001-{BD2A9899-68C1-4E22-989E-EC16D57BF384}) gateway on session index 2. [XAPI GATEWAY 18 60] (8)

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Event Type:      Information
Event Source:      MSExchangeMTA
Event Category:      Operating System
Event ID:      9158
Date:            6/27/2005
Time:            5:45:21 PM
User:            N/A
Computer:      CRP0001
Description:
(BASE IL INCOMING RPC(18) Proc 0)           Thread created, type = 6 (see SBCDERR.H) (4)

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Event Type:      Information
Event Source:      MSExchangeMTA
Event Category:      Operating System
Event ID:      9159
Date:            6/27/2005
Time:            5:45:21 PM
User:            N/A
Computer:      CRP0001
Description:
(BASE IL INCOMING RPC(18) Proc 0)           Thread exiting, type = 6 (see SBCDERR.H) (4)

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Does anyone know what this means?

Thank you,