Macros warning message when processing a custom form

[Bingo]

I created a custom form with several user defined
fields. In my VB app, I process all the emails in the
Inbox. If the message class matches the custom form, the
app will read values from all the udfs. Everytime, the
app starts processing an email, a warning message pops up
several times.

Warning: Opening "..."
The form for this item has not been registered in this
folder or in your company's forms library. Because this
item contains macros, which ...

The form is currently published in the Organizational
Forms Library. I don't have any VBA code inside of the
form. I read about one-offed and I already un-checked
the box on the property page. But I'm still getting the
warning message. During VB debugging, I never saw this
at all. How should I do to get rid of this warning?
Thanks.

 

[Bingo]

Problem solved. I mis-spelled a UDF.