It took me many hours to figure this out so I thought I would share what I discovered to make it easier on others.
1. Flash Builder 4.7 no longer has Design Mode (being able to design forms graphically). 4.6 was the last version to support it.
2. Adobe will not sell you 4.6 (or 4.5). They only sell 4.7. They suggest you find a retailer who has an old box.
3. Don't bother complaining, the word is "real programmers don't use design mode".
4. I called support yesterday to get some questions answered. I was told the wait time is over 2 hours and I can't leave a callback number. (At least at that time, they only let you leave a callback number for product returns - which I also did.)
I spent over 8 hours on this yesterday at a cost, in terms of lost revenue, of 4 figures. I hope this saves you some time.
Blake