C2H Compilation Error - Explicit Inclusion

It could be just a namespace collision with some other library used by your Quartus II project. For example if I wrote two custom components both with their own module called "MyWidget" Quartus II will flag this since you have two implementations of the same module. That is what I suspect is happening in your case, C2H is generating a module that happens to have the same name as something else used elsewhere in your hardware design.