tyBetter to attach the traceback.txt file than copy/past the file content
Without context on when and where it happens I will assume it's because of the room wallpapers (that error can occur because of it) so open the console (shift+O) and type in the following commands :
player.room2_picture_index_left = -1
player.room2_picture_index_middle = -1
player.room2_picture_index_right = -1
This will reset the room wallpaper.