I had a helpful email this weekend pointing out that, for OpenBSD, the Qt tools uic and moc are renamed to uic3 and moc3. Evidently, the path to those utilities should be read from the $MOC and $UIC variables. One works, one doesn’t.
I had just copied the stock KDE admin directory, and apparently, $UIC_PATH is being used instead of $UIC. I’ll fix that for the next version, but if you’re compiling Bookcase on OpenBSD, or probably any other *BSD, you might want to either set the $UIC_PATH variable, or modify the configure script.