"Cannot copy or restore to snapshot control file"
*Cause: A control file copy or restore operation specified the name of the
snapshot control file as the output file. It is not permitted to
overwrite the snapshot control file in this manner. Other
methods are available to create the snapshot control file.
*Action: Specify a different file name and retry the operation. If this
is a restore, then the restore conversation remains active and
more files may be specified.