Make sure you have a wallet set up and open.
Go to Settings -> KDE Wallet. Make sure there is a wallet set up there. Also make sure "Use KWallet for the Secret Service interface" is checked (that's the new thing).
Then open up KWalletManager from the app menu. It may show the wallet as closed, that's normal. Click the Open button and make sure you can open the wallet.
If all that works, we can troubleshoot further.