I don't know if this was mentioned or not.

I know the cause, but I figured I'd post here in case others may have an issue. If your keys suddenly stop working, (like the 'e' key for end turn), check to see if you have caps-lock on. Turning it off solved my problem. It only seems to accept the lower-case letters that are entered.
This includes all letters on all parts of the map/battle system (on the new system, obviously).