I ran into this error when I was trying to embed an swf into one of my classes like this:
[Embed(source='assets/aaa.swf',symbol='bbb')]
private var bbb:Class;
It gave no error in Flex Builder, but when I was about to build the application using standalone compiler and deploy to production, an error was thrown out:
unable to resolve 'assets/aaa.swf' for transcoding
The solution was easy: just to append a '/' in front of assets like this:
[Embed(source='/assets/aaa.swf',symbol='bbb')]
private var bbb:Class;
Damn unbelievable. I was wondering why the compiler in FB didn't complain in the first place.