It might change behavior with the FN or (CAPS + FN) keys then, see ...
Any way to keep the Fn key enabled?
Special Function Key Shortcuts Don't Work ...
Also see ...
Keyboard shortcuts in Windows
It seems like they are acting as if they are num-pad keys 4&6 (I'd bet up/down would give you symbols too). Is there any kind of num-lock type function with the keyboard, like to make a set of the keys work like they are the num pad? Also if there's an "fn" type key I'd try holding that down whilst doing the key press to see what happens.
I don't know of any concrete way to fix the issue though, sorry! (well, aside from plugging in a full-size keyboard )
