UltimateListCtrl and IndexError

Hi all!
I'm using a UltimateListCtrl with a couple of items in it.
As soon as I create the selection on the items works like a charm and
no issues arise.
Altough I'd like to empty it and refill as soon as a RadioBox event is
generated.
As I do that the list does get updated but clicking on items causes
the following problem, I put the traceback right here:
http://pastebin.com/ucWxx9bS

My code is almost the same as the following:
http://pastebin.com/gmxmVmwD

What am I missing? I can't figure out the problem!

Thanks in advance.