This is very weird! I had a different plugin for custom post types called Custom Post Types UI installed. When it was installed, the Gravity Forms + Custom Post Types plugin form Gravity forms worked just fine (this plugin allows the general post to blog function in GF to be applied to a selected Custom Post Type) but I decided to switch to CustomPress because it seemed to have more options and definitely more support (or at least I hope)!
But when I installed CustomPress, my custom post type "opportunities" was gone and I had to recreate it. Gravity Forms started acting funky and launching the preview mode like it was an unknown mimetype and the form no longer works. Now, no matter what I do, the Gravity Forms + Custom Post Types plugin will not display the option for submitting the form to a custom pot type. AAAAHRRRG!