Dreamweaver crashes on me as well...
I have created a fairly long form and saved it as a preset. When I click Finish and the box with the status bar pops up, the bar gets to about 50% and everything stops working. Dreamweaver freezes and I have to shut it down. I reinstalled the extension in case there was a glitch but I am getting the same result.
To get a better idea what the issue may be, I created a form using a template in FormBuilder. it works just fine so I must assume it's the form I created. Unfortunately I do not receive any error messages when it crashes but I could send the debugging code created by Windows (XP). I use Dreamweaver CS3.