thanks for asking.

You may have accidently pressed the Menu button - which would usually 
display the Remote Buddy menu. Keynote, however, does capture the 
screen during its presentation, so Remote Buddy can't display its 
overlay. To make it possible for Remote Buddy to display its menu, 
please activate the checkbox "Exposé, Dashboard ... may use the 
screen" in the "Presentation" category of Keynote's preferences.

The mapping of the buttons is then displayed to you whenever you 
press Menu. Do, however, note, that you should dismiss the menu again 
by pressing Menu, so you do actually trigger the actions for Keynote 
instead of navigate the menu.

I don't see any error sources beyond that. Remote Buddy uses 
AppleScript to communicate with Keynote - which should always work in 
the same way.

Best regards, 
Felix