Hi, I also encountered the same problem every time I compile the examples of Away3D where that I have downloaded at https://github.com/away3d/away3d-core-fp11 .

Btw I’m using Flashdevelop IDE,
Every time I “Add to Library” the away3d4.swc file.
It the problem always occurs and says

col: 43 Error: Access of undefined property Cast.
col: 44 Error: Access of undefined property Cast.
col: 21 Error: Definition away3d.utils:Cast could not be found.

So I tried to use the template if the away3d.utils is missing.

And yes unfortunately away3d4.swc doesn’t have away3d.utils on it like what maddog said.

So what I did I download a Away3D 3.6 version and double checked if it has away3d.utils.

then I import the library of Away3D and add it to Library, where in flashdevelop

Projects>Properties>Classpath
//Note you should use this method for importing external classes to make
//things work since this method works for me. hehe

So in summary I have 2 libraries in my Project which is
away3d4.swc and the src of Away3D 3.6 .

And BAAAM ! It should work fine.
WORKS FINE WITH ME! :D