The manual says.
CAUSE: The database stored in battery-backed memory on the CPU board did not checksum properly.
The system performs the checksum test once a day to verify the integrity of the database. The
memory chips may be faulty. However, there is one way this condition can occur without the
memory being faulty. If the processor is doing a write into protected memory at the exact
moment an external interruption occurs (loss of power, pressing the reset button, etc.), the data
written to the write-protected memory may be corrupted.
ACTION: Save the database to the computer via an “axx” file as soon as possible. Do not save the “axx”
file on top of a previously known-good database because this database may be too corrupted in
a critical location. Keep in mind that the “Backup Database” may be a non-corrupted database.
If the existing database appears corrupted, default the system's database, without the voice
processor connected. After the system powers up, the default database LED will be on. Reset
the system one time to force a “Backup Restore”. If the “Backup Restore” reveals a corrupted
database, restore the last known “axx” file.

Answer The Phones
Telephone Engineer
UK