I've tried all the suggestions so far but no luck.  I can not ever get 
/dev/cua* to work properly.

Even cat fails:

# cat < /dev/cuaa
ksh: cannot open /dev/cuaa: Device not configured


So the fundamental problem is this "Device not configured" error.  How 
is OpenBSD supposed to be configuring these devices and why is my system 
not doing so?  This is a completely clean install of OpenBSD on the 
machine after completely formatting and repartitioning the hard drive.

There's something missing and it's probably something simple but I've 
stared at it for so logn now that I'm likely missing it entirely.