We don't know what's going wrong, so we don't know what you're doing wrong. I also have no idea what you're trying to do.

However, the first thing that comes to mind is that you're attempting to access your hash with a substr of the key. Well, the substring isn't a key to your hash.

Furthermore, I recognize this data structure as one we've seen many questions on before. Have you even tried to:

1. Write out what you're trying to do
2. Figure out what you need to get done
3. Think at all?!!

------
We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.