thanks for asking.

Have you really worked through all of the possible error sources 
provided in the FAQ?

I.e.: is Bluetooth turned on? For longer than just a few seconds 
before trying to connect a remote control? 
Is the "Bluetooth Receiver" in Remote Buddy turned on? 
Is the Kernel Extension installed? (it isn't if you don't see the 
"Bluetooth Receiver" in Remote Buddy) 
And most importantly: was the Setup Wizard used for initial pairing?

And there are more possible error sources (currently not in the FAQ):

Is any other software running on your computer that uses Bluetooth at 
the same time?

Are any other Bluetooth devices active / in use with the Mac at the 
time of pairing?

You don't need to uninstall DarwiinRemote. You just shouldn't run it 
at the same time as Remote Buddy.

Please also don't use System Preferences to remove the remote 
control. That will undo any pairing previously performed with Remote 
Buddy and require you to repeat the "Setup Wizard" procedure.

If this does not help you solve the problem, a short step-by-step 
description of what you do when trying to pair the remote control 
with your Mac as well as answers to above questions would be very 
helpful in trying to find the cause of the problem.

Best regards, 
Felix