User works in the Editor window most of the time. After prolonged inactivity, the database's idle timeouts the connection. When the user tries to run a query after being disconnected, they get an error "Unknown Error: ORA-6831047".
Attempting to reconnect to the database gets the same error "Unknown Error: ORA-6831047." Shutting down Toad causes a crash with a series of error messages regarding memory corruption.
If your Oracle client is 8i, it may have issues with disconnected or dropped sessions. Upgrading to the Oracle 10g client may resolve the issue.
If you already have a 10g client, please contact Quest support.