Are you running firmware version 4.31? If so, then that's the reason for these errors and the database corruption. There are two solutions.
1. Install firmware 4.30 and install the patch to not update the firmware via WiFi
2. Install firmware 4.30 and do not sync. Keep WiFi off.
The problem is that 4.31 is rather buggy and is known to corrupt the database. I suggest you read the thread on the 4.31 firmware.
Firmware 4.31.19086