Error in RMAN backup logs

 Hi,
I got following error message in logs for RMAN backup of a database.

Starting Control File and SPFILE Autobackup at 18-SEP-10

released channel: d1

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03009: failure of Control File and SPFILE Autobackup command on d1 channel at 09/18/2010 22:24:46

ORA-00447: fatal error in background process

I also came across following alert from Grid Control around the same time:

Occurred At= Sep 18, 2010 10:24:25 PM EDT
Message=Access violation errors have been found in the alert log.
Metric= Access Violation Status
Metric value= 1
Severity= Critical
Acknowledged= No
Notification Rule Name= Database Availability and Critical States
Notification Rule Owner=