Why does this code work fine on Windows, but give a compile time error on the Xbox copy?

What is the error?

I've run JigLibX on the Xbox before and it's compiled fine. Are you sure you haven't changed something?

Dunno. Post your definition of transformRate, how it's accessed from that function, and of course, posting the actual error message, I'm sure that will help.

What's the error it gives you?

Sorry, should have posted that. Its:

I may be remembering wrong, but isn't Vector3 a class on the XBOX? If so, then you need to assign a new Vector3 instance to "result".

I'm pretty sure Vector3 a struct for both, a class would give a sligtly different error right when you assign X.

Regardless, I can reproduce the problem now with XNA 3.1, possibly it's some changed behavior. What you have to do to fix it is add
  

    result = new Vector3();


at the top of the function. It just seems that the compiler is not smart enough to realize you're indeed assigning all three components. I suspect the standard requires the initialization with new Vector3() anyway, but I'm not a language lawyer.

See this thread for a full explanation. The issue relates to the tool used to generate the stub assemblies for the Xbox/Zune and how they handle struct initialization.

The easiest way around the issue is to always call the default constructor for structs.

Ah. Useful information, thanks.