oracle error - ORA-00232: snapshot control file is nonexistent, corrupt, or unreadable

ORA-00232:	snapshot control file is nonexistent, corrupt, or unreadable
Cause:	The snapshot control file was found to be nonexistent, corrupt, or unreadable during an invocation of cfileUseSnapshot.
Action:	Call cfileMakeAndUseSnapshot again (or for the first time).

oracle error - ORA-00231: snapshot control file has not been named

ORA-00231:	snapshot control file has not been named
Cause:	During an invocation of cfileMakeAndUseSnapshot or cfileUseSnapshot it was detected that no filename for the snapshot control file had previously been specified.
Action:	Specify a name for the snapshot control file by calling cfileSetSnapshotName.

ORA-00230:	operation disallowed: snapshot control file enqueue unavailable
Cause:	The attempted operation cannot be executed at this time because another process currently holds the snapshot control file enqueue.
Action:	Retry the operation after the concurrent operation that is holding the snapshot control file enqueue terminates.