go first here and do check-list:
it lists supported/non-supported/check-at-runtime features - as you could use a feature that is not supported at your device (application could work in Air/Flash Builder device emulator though)
What is happening in your application when it starts? Does it load video/audio or does request to local or remote content?
I dont know about the S but I know a couple of people with Wildfires and neither of them can find any of my apps on the market even though they have 2.2 Froyo
The app do nothing (special I guess), it is just Flex Mobile Project - View based application - everything generated by Flex Builder 4.5.1 (in a new workspace as suggested by IDE).
I changed supported profile to mobileDevice but it also did not solve a problem.
I would like to mention that there is no problems when running this app "on desktop".