You are using very old wallet version. Right now we are at 1.2.1 version. If I am not wrong, at block 100000 the blockchain was forked leaving behind nodes bellow 0.6 version. I am not familiar with how Sia worked at that old versions, but can the software provide you a wallet seed for you? If yes, then is trivial: Install the latest version, wait until blockchain is synchronized and then use the seed to unlock your wallet.

If you don't have a seed for your wallet, best go to Slack and ask about your case in the #help channel. Devs are very active there