INDIRECT.EXT, from Laurent Longre's Morefunc 4.2 Add-in, is giving me a
"#VALUE!" error message in the cell with the formula:

=SUM(INDIRECT.EXT("[MyBook.xls]MySheet!$A$1:$A$3"))

when MyBook.xls is closed; it only works when I open MyBook.xls.

From what I've seen in the help file and other posts in this forum, it is
supposed to work for closed workbooks and for ranges of cells.

How can I get it to work? Perhaps there is an update, or a way of using
this function that I'm not aware of?

Thanks.