A2003 SendObject error with earlier or later versions of MS Office

[PW]

I have this line of code in our Access2003 application
DoCmd.SendObject acSendReport, , acFormatRTF, strEmail, , , "Deposit
Request"

We have clients all over the country who execute this line of code
successfully. Recently, I was made aware of an issue at a new client.
This client has 4 pcs. 2 of the pcs are using Office 2007. 2 of the
pcs are using an earlier version of Office. I am getting an error on
the 2 pcs that use Office 2007. You can see the report outputting to
a .rtf format, but then I get an error (an error that I am using
through an error trapping routine so I can't tell you the exact error
but the email is not getting sent).

Does anyone know why this issue might be occurring in this instance?
Thank you. -Kristin Williamson