I am having problems merging indexes with stop words.

I have created two index using the stop words features. I merge these 
indexes (Merge #1), and everything works just fine. I then created two 
more indexes. I merge them together (Merge #2), and everything works 
just fine. But when I try to merge Merge #1 and Merge #2, I get the 
following error:

   err: Header WordCharacters in index 1020014164-2.idx doesn't match 
output header

On the other hand, if I created my original indexes without stop words, 
then I am able to merge Merge #1 and Merge #2.

Does anybody know how I can resolve this problem?

--
Eric Lease Morgan
http://www.infomotions.com/