Can you try running a simple flex app that just has a button with a label to see if that works?
Does the same Flex app work in the 32-bit version of Flash player?
Thanks Anirudh for your reply.
I've tried the same example that you suggested, but I had no luck. My Flash Builder 4.0 is running on Windows Vista (64 bit).
What could be the cause for this?.
If you can see the preloader, flash player is present.
The preloader loads RSLs required by Flex and then you see the main app. For some reason this part is not working for you. This is the part we have to figure out.
To see if this is player specific, can you also try your app in Google Chrome/Firefox?
Also to confirm: Can you change your link type to "merged into code" in Project properties -> Flex Build path to see if that affects this?