Error - The remote server machine does not exist or is unavailable

Hello - I'm getting this error message in a mail merge I'm doing from Access. It seems to be a common problem; 1st time through, it works fine, then blows up the 2nd time.

I've followed the advice I've found about declaring specific object variables for the Word app & doc, and then closing and setting them to Nothing at the end of the routine, but I'm still getting the error.

This started happening when I added a routine to loop through ActiveDocument.Tables (to set the font, size and column widths). It blows on the 2nd time through on the line:
     For Each tbl in ActiveDocument.Tables

Is there another object variable for the mail merge result that has to be set to empty?

Any help much appreciated

Thanks

Mark