Obvious first thing to check would be that you have a top-level context with the same name that the script is expecting. There's a property definition near the top that seems to supply the name, but in fact the script doesn't use it, doesn't handle the case where the context doesn't exist in any way, and doesn't handle a context which is nested inside another. Brings to mind the infamous quote:
"If builders built buildings the way programmers write programs, then the first woodpecker that came along would destroy civilization."