I finally found a workaround to replace the NETWORKDAYS function at the
website
http://www.dicks-blog.com/archives/2...-addin-part-2/.
NETWORKDAYS EQUIVALENT
=SUMPRODUCT(-(WEEKDAY(ROW(INDIRECT(start_date&":"&end_date)))< 1),(-(WEEKDAY(ROW(INDIRECT(start_date&":"&end_date)))< 7)),-(COUNTIF(holidays,ROW(INDIRECT(start_date&":"&end_ date)))=0))*(1-2*(start_dateend_date)).
This seems to work. Thanks for all comments.

"Ron Bridgeman" wrote:

When I enter "= NETWORKDAYS(DATE(2008,3,1),NOW())" into a cell in a
worksheet, it calculates perfectly. However, the second time that I close and
reopen the workbook, I receive a "#N/A" error. (I can close and reopen the
workbook once without an error.) The Analysis ToolPak is installed.

Can anyone explain why this is happening? Thanks