1046: Type was not found or was not a compile-time constant: Vector3D error while compiling

I am using Flex Builder 3.2 for compiling my flex code and i am getting errors during compilation.

1046: Type was not found or was not a compile-time constant: Vector3D

1046: Type was not found or was not a compile-time constant: Matrix3D

1046: Type was not found or was not a compile-time constant: GraphicsStroke

I am not using any of the classes mentioned above. Please let me know if I am missing something.