Sounds like the build boys messed up
Post your problem to the OpenZ guys, probably just needs to be rebuilt. Since it is hardcoded into the kernel, there isn't anything you can do about it anyways.
I've played with the OpenZ kernels in the past and they are nice. I'm currently running Sharp's latest build. It also has improved.
Have you seen the SL-860? I'll probably be ordering one soon
Or at least I'd like to think so
As for:
"I had problems in the past with flashing where my zImage somehow ended up with a .bin extension."
Welcome to Windows my good man

I had to correct a couple hundred rpm's that got d/l'ed as .ram (RealPlayer).