Maybe you are on the cvs build? There was/is a bug with chout.flush() (which crashed) and IO.newline() didn't correctly force a flush. Ge was working on a fix which I would expect to be in cvs right now as the cause had been pinpointed.

Good thing I kept notes here; http://wiki.cs.princeton.edu/index.php/ChucK/Bugs/Release as I had forgotten the exact details.

Yours,
Kas.