I have a similar problem ... just had to replace a failed PVP600 with new one last month. Previous PVP used a CF memory card while the new one uses an SD card.
Didn't have an SD card so I used a USB stick and config'd for PVP to use the USB.
Re-install went fine and the unit boots up properly with the original MER file, but the trends won't populate with anything other than real-time data.
Any suggestions?