sorry but I restarted the game all over again after reinstalling it just in case and i still get the exact same error "tenky_sprite2 is not defined" . ^^'
Perhaps there is a problem with either the real name of the sprite or it has been moved out of his folder ? I couldn't check myself as we have no access to thoses informations in the distributions versions of a ren'py game.
It would be weird though considering most peoples have been able to play without encountering this issue...