.xls Attachments Arrive Corrupt and Unable to Open

OK.  I have been fighting with this for a while now.  

Server Setup:
Server 2003 Standard Edition running Exchange 2003 Standard Edition.  All service packs and updates have been installed.  No issues sending mail or receiving mail outside of this attachment issue.

Situation:
An Excel spreadsheet contains all the inventory availability for this company.  The spreadsheet is known as "The Availability."  Lately, when sending the availability, several recipients respond that the attachments is corrupt and will not open.  The list goes out to about 500 recipients.  Somewhere between 5 and 30 recipients respond each time that they cannot open the attachment.  If the attachments is sent again to the same users individually it opens normally.  

Troubleshooting Steps Taken:
*  ISINTEG and ESEUTIL have been run against the information store with very few errors and all of them fixed.
*  Attachment has been sent from computers running AV and from computers running no AV with the same result.  
*  Email scanner (Symantec Mail Security 6) has been disabled to no avail.
*  Attachment has been sent from Outlook 2002, 2003, 2007, and OWA with same results.
*  SMTPSVC1 Logging has been enabled and Diagnostic Logging for MTA connections, general transport, and NDRs have been enabled at Maximum (discussed later.)
*  Problem has been recreated by sending from 7 different computers and by sending not only to the 500 recipient list, but to individuals as well.  
*  Problem has been reported by recipients with dozens of different domain names (not specifically msn or yahoo, etc.)  
*  Company mail server does not show up on Blacklist servers at mxtoolbox.com and is not listed in the SBL, XBL, or PBL on spmahaus.org.  
*  Valid PTR record exists for the company.
*  Mail is sent using DNS to forward (no smarthost or 3rd party outbound mail scanners are used.)
 
Sending user reports no NDRs delivered outside of ones to recipients that no longer exist.  Log files indicate 2 primary NDRs identified listed below:

 Event Type:      Warning
Event Source:      MSExchangeTransport
Event Category:      NDR
Event ID:      3022
Date:            4/24/2008
Time:            7:15:07 AM
User:            N/A
Computer:      SERVER
Description:
A non-delivery report with a status code of 5.5.0 was generated for recipient rfc822;user@recipientdomain.com(Message-ID <5E33EB06A83D604CB90E19E607DDCB027BC43D@server.domain.com>).  
Cause:  This message indicates a generic protocol error (SMTP error).  For example, the remote SMTP responds to an issued EHLO with a 500 level error and the sending system will QUIT the connection and report this with NDR indicating the remote SMTP server canÆt handle the protocol.    
Solution:  View the SMTP log or run a netmon trace to see why the remote SMTP server rejects the protocol request.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

And This NDR is the next most common in the logs, though this one usually ends up being a misspelled domain name.

Event Type:      Error
Event Source:      MSExchangeTransport
Event Category:      NDR
Event ID:      3018
Date:            4/23/2008
Time:            4:47:20 PM
User:            N/A
Computer:      SERVER8
Description:
A non-delivery report with a status code of 5.4.0 was generated for recipient rfc822;eric@andersonshowplace.com (Message-ID <5E33EB06A83D604CB90E19E607DDCB027BC421@server8.fisherfarms.loc>).  
Causes: This message indicates a DNS problem or an IP address configuration problem  
Solution: Check the DNS using nslookup or dnsq. Verify the IP address is in IPv4 literal format.
For more information, click http://www.microsoft.com/contentredirect.asp.
Data:
0000: ef 02 04 c0               ï..À    

The only indication of trouble in the SMTPSVC1 Log file is this line:

220+bay0-mc6-f14.bay0.hotmail.com+Sending+unsolicited+commercial+or+bulk+e-mail+to+Microsoft's+computer+network+is+prohibited.+Other+restrictions+are+found+at+http://privacy.msn.com/Anti-spam/.+Violations+will+result+in+use+of+equipment+located+in+California+and+other+states.+Wed,+23+Apr+2008+17:00:12+-0700+ 0 0 309 0 32 SMTP - - - -


This only started happening in the last month.  It has happened with 3 different spreadsheets now, each created differently.  One is generated by doing an export from a database program into an xls file.  One is manually created.  The third is created by doing an export from a database program different from the first database program.  

I haven't got a clue as to what to look at next.  If anyone has any ideas please let me know.  I can provide whatever information you need if it is not listed here.  

Thanks in advance.  Start Free Trial