Djaydino YOU THE MAN !
It work now.
I updated the "UiButtonArrayIndex" action and added a NEXT FRAME EVENT like you said but not at the same place because I don't use the first panel where you can choose the categories. I added this NEXT FRAME EVENT between "Set Answer Button" and "Get Next Answer". I don't know if that's what made it work but in any case it works perfectly.
Thanks again djaydino, great thanks!