Had to qualify build for AIR 18 with swf-version for File.cacheDirectory

I ran into an odd issue today, I created a build using AIR 18 and was getting undefined for File.cacheDirectory. In my build parameters, I only had -target-player 18.0. I added a -swf-version parameter (=20), which I hadn't had to do with AIR 15, then it worked. BTW, I am compiling on Windows Vista 64-bit with the v1 AS compiler. I am in the process of moving my development to the v2 AS compiler, maybe that will solve this issue.

-jonathan