Due to the hack that drained The DAO of much of its ETH supply, the DAO was discontinued as an actual organization / entity, though its "The DAO" token still exists and is tradeable. The DAO Refund option that is visible on The DAO's wallet screen is there to offer DAO token holders a chance to refund their DAO tokens at the original rate of 1:100 (as in 1 ETH : 100 DAO).
In order to perform this refund, you will need to have at least enough ETH (we recommend around .01 ETH to be on the safe side) in your specific DAO-holding ETH addresses to cover the ETH transaction fees associated with moving the tokens. Remember that Jaxx is an HD address, which means it splits your ETH balance between multiple addresses. You can see all ETH addresses and their individual DAO and ETH balances at Tools > Display Private Keys > Display Ethereum Keys.
If you have performed the DAO Refund option but it was unsuccessful, please review this article.