I assume this is a continuation of the project discussed here:
https://www.msofficeforums.com/mail-...-header-2.html
Your post refers to macros, but there don't appear to be any in either document (even though the RPT.doc gives a macro warning). Likewise, your post refers to INCLUDETEXT fields, but there are none in either document. And, yes, INCLUDETEXT fields do work - even for mailmerges - as previously discussed. Furthermore, the Mailmerge SQL prompt refers to what is, ostensibly, yet another document that you're presumably using as a datasource.
As it stands, I have no idea what the problem is. What is the origin of all the data? An excel workbook, perhaps?