Try each of the following steps in order, attempting the merge again after each step, until the issue is resolved:
  1. Be sure to log into The Raiser's Edge using the RE7 icon and not the BBNC Plugin for RE icon.  Please see our solution on when to use the BBNC Plugin icon (BB555128) for more information.
  2. Recreate the letter template.
  3. Recreate the parameter file.