You may have signed up with the wrong Serial Number.
Your serial number is both on the login page, and on the system page. It looks like this:
Deeper-Wire-HWA-144cc9b1b3af|b6f32b89f9958ace
You must copy your SN from system page (do not copy mine!) and use that when you set up the wallet. Then you download the wallet that is generated and bind it to your DPR device.
If you mistakenly put the wrong SN then you will not get the DPR tab and you may be stuck staking to a wallet that is not even connected to your device. If this is the case, you have to contact DPR team to find out what to do.