"data file %s has not been identified"
*Cause: This data file was not in the control file after an incomplete
recovery or CREATE CONTROLFILE. Since information from its
header is needed for standby database recovery, we can not
create a standby control file.
*Action: Find the file and bring it online. If desired it may be taken
offline again. If you intend to drop this file, then taking it
offline with the DROP option will avoid this error.