@AceTracer: *Never* reboot a Kindle with a custom update file, it won't ever successfully install anything custom @ boot, and you'll end up on the nice screen shown on your screenshot.
If you need to disable the hack, and you still have access to the userstore over USB, just remove/rename the linkfonts/auto file, and restart.
Now, in order to fix the specific K3 issues with some fonts, either:
1/ Find a font that your Kindle will handle (As I can't reproduce this, I have no idea what exactly is the cause of this).
2/ Use the bci or autohint setting, and restart.
3/ Give up, disable the hack, restart, and uninstall it
.
On a sidenote, you seem to have a few books that fail to index because of a wrong PID (apparently...), ASINs B002WGC8PU & B000FCK3X2