i have been using fdt for about a month now, working on a air desktop app. untill now, everything worked fine. but yesterday, i tried to create an other project, and nothing works anymore: when i try to launch the app, it launches the "external swf viewer" instead, with nothing in it. I bet this comes from the launch/debug settings, but i don't remember changing the ones of the older project.
I a little bit lost with the sdk's too... i found one that seemed to work, but i really don't know why. (when i try one downloaded from adobe's website, fdt tell me that it cant find any sdk in it) I could also come from that.
If you need more information please tell me.
I have had a similar problem. Try this: http://bugs.powerflasher.com/jira/browse/FDT-3168 Worked for me!