Were these archlog files backed up?
6025, 1, "no backup of log thread %d seq %d lowscn %s found to restore"
// *Cause: An archive log restore restore could not proceed
// because no backup of the indicated archived log was found.
// It may be the case that a backup of this file exists but
// does not satisfy the criteria specified in the user's restore
// operands.
// *Action: None - this is an informational message. See message 6026 for
// further details.
6026, 1, "some targets not found - aborting restore"
// *Cause: Some of the files specified for restore could not be found.
// Message 6023, 6024, or 6025 is also issued to indicate which
// files could not be found. Some common reasons why a file
// can not be restored are that there is no backup
// or copy of the file that is known to recovery manager, or
// there are no backups or copies that fall within the criteria
// specified on the RESTORE command, or some datafile copies have
// been made but not cataloged.
// *Action: The Recovery Manager LIST command can be used to display the
// backups and copies that Recovery Manager
// knows about. Select the files to be restored from that list.