I downloaded the swc file from here: http://developer.yahoo.com/maps/flash/flexGettingStarted.html
And put it in my flex 3.0 lib folder - just like where all my other 3rd party libraries are in place, however with the yahoo flex map lib, i get that error.
Any ideas? Appreciate your help, thanks.
okay nevermind, i downloaded the swc library from here instead: http://developer.yahoo.com/flash/maps/
Did a clean build and it worked.