That's a hard coded, undocumented limitation in the loader... :oops:
The code of the jaw-loader is around 6 years old and i've never touched it since then. There is a configuration variable for it, but it's not public. I'll try to get this fixed somehow in the next version or at least exit more gracefully than with an ArrayOutOfBounds from deep inside the Loader.
JAW isn't a very good format anyway...
(3DS and ASC have such limitations too, but they are implied by the format specs themselves).