Hello, I also have the same error when trying to publish a customized form.
Could you elaborate on what the exact file extension should be? This is my
first time trying to customize forms. Thanks, JHV.

"Jackie" wrote:

What I have done is publish the form with an extension.. then go back out and
delete the old one and rename the new one.. This is the workaround, because I
am having the same issue..

"Shelly" wrote:

Help! I'm trying to customize a form in Outlook 2003 with Small Business
Contact ...when I click publish I get "Unable to determine where to save this
form due to an error." ...then I click "OK" and get the "Publish As" window
then click "OK" and get the following message "Unable to successfully publish
the form due to a MAPI error. OpenProperty: cannot open properties which are
computed." I can't find anything in the help files or documentation about
this.
Thanks for any help you might have