"BonusActionBarFrame.lua attempt to index a nil value" plz HELP

[Dorian]

i don't know what hapened the game was working fine.I started getting this message in-game:
[string "Interface\FrameXML\BonusActionBarFrame.lua"]:232: attempt to index a nil value

and it apears whenever i cast a spel or push any button in the game.Its realy annoying plz help.

i went into my interface folder bun i couldn't find any FrameXML folder