I'm sorry, but an uncaught exception occurred.
While running game code:
File "renpy/common/000statements.rpy", line 485, in execute_call_screen
store._return = renpy.call_screen(name, *args, **kwargs)
File "game/screens.rpy", line 1566, in execute
File "game/screens.rpy", line 1566, in execute
File "game/screens.rpy", line 1575, in execute
File "game/screens.rpy", line 1579, in execute
File "game/screens.rpy", line 1580, in execute
File "game/screens.rpy", line 1581, in execute
Exception: Imagebutton does not have a idle image. (auto=u'./buttons/negociate_%s.png').