Using FireBug, I found that the DetectFlashVer() wasn't firing. Huh?
I checked the files, made sure I hadn't changed any configuation, double checked with the team that I all the code. Everything was there, as they had it.
Only upon further investigation did I realize that I was missing the AC_OET.js and /history from my template. This seemed strange in the beginning, but the client insisted everything was running fine for them. I had to assume it was my configuration, trying to run Flex 3.5 from Flashbuilder 4.6, I must've been doing something wrong.