1. what is the address holding the 20BTC?
2. is it transaction of satoshidicke sending back a prize?
3. is the wallet damaged?
if it is a transaction sent but never confirmed i is possible to create raw transaction using same inputs. Think about it as double spend. Also the pywallet is still supported by JackJack.
They are all transactions to satoshidice. They aren't all concurrant transactions, they're spaced out and of a small enough amount that I didn't take too much notice at the time, as I was playing with some huge amounts. (Note to self, the martingale NEVER works in the long term).
I made several backups, I'm going to try and delete the transactions using pywallet and rescan. Is this an appropriate course of action? I don't think the wallet is damaged.
Screenshot of one of the transactions. http://imgur.com/3WUPNdD