John,

My guess would be that it has something to do with the custom code you have written in this form, prehaps a method that you have subclassed. One way to test it is to create a test form, put your cursor in the data environment, use the same button and put your code in the afternew method. See if it works.
Also, I'm not sure you want to be lauching another form from this method. This may not be the place to do it.

Deb