Well, I finally found the issue, a corrupted mm.cfg file in /Library/Application Support/Macromedia. I deleted the file and then adl ran just fine.
I'm having the exact same problem. After I upgraded from FlashBuilder 4 to 4.6, adl does not show any content (no window or anything).
When I went to look for mm.cfg, I did niot find it in the library, but rather in my primary system user folder. So I tried putting it in the trash, but adl still won't work. I also tried putting mm.cfg into the library/Application Support/Macromedia, and adl still wont work.
When I open mm.cfg (with TextMate), I see nothing.
What to do?
Firefox altered my mm.cfg in my home folder. I edited the PreloadSWF= entry. My mm.cfg now reads as (and this works for me):