xtrabackup error

xtrabackup interrupted with following error.
this is RPM version.

100814 10:20:21 InnoDB: Operating system error number 9 in a file operation.
InnoDB: Error number 9 means ‘Bad file descriptor’.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.1/en/operating-system-erro r-codes.html
InnoDB: File operation call: ‘close’.
InnoDB: Cannot continue operation.