GetChar() freezes in Windows

I'm currently experimenting with Psych Toolbox so that I can document
it in a book I'm working on. I have some other questions I may ask
later, but at the moment I'm having trouble with GetChar on Windows.
Any time I call it, Matlab goes into an infinite loop, maxing out the
CPU, and has to be killed from the Task Manager. This is using version
2.54. Any ideas why this is happening? KbCheck, KbWait and Ask all
work fine.

Thanks,
Mike