Possibly Dreamweaver corrupting it's local preferences? Althouh it's pointing to your Application folder (which is more global). Hopefully an Adobe rep can chime in here and suggest ways of recreating your Dreamweaver configuration folder? Otherwise, you may need to re-install Dreamweaver (back up your site definitions and extensions first!).
I've seen this a few times, and it's usually caused by a problem with the local ProjectSettings file. The workaround is to re-create this file.
See the post by "redheads" here for instructions: http://community.phonegap.com/nitobi/topics/dreamweaver_now_cant_build _after_todays_update_please_help#reply_10869042
Hopefully that helps, but if not be sure to reply back.