Error code 128 means the PM5 is having trouble with external software. This happens most frequently with the third-party rowing software RowPro. If you are using RowPro, try shutting down all programs running on your computer and then reboot the computer. You can also try connecting with a different USB port on your computer. If the error persists while using RowPro, you will need to contact Digital Rowing for support at email@example.com. If you are using Concept2 software such as the Concept2 Utility, ErgData, or Venue Racing application, please contact Concept2 for assistance.