The transaction references a previous transaction that has not been confirmed yet.
The previous transaction hasn't been confirmed because it too references a transaction that hasn't been confirmed.
That transaction appears to have not yet confirmed because the fee is too small, and it is taking a long time to go through.

It could be an honest mistake, but the fact that the previous transactions are all referencing the same address means there is a small chance it could have been done on purpose. I'm not sure if the sender would be able to do a double spend, but if so this would be a clever way to buy some time.

All you can do is wait for this transaction to clear:
https://blockchain.info/tx-index/97387217/1