Oracle Error Message
RMAN-06081: error reading datafile header for datafile string, code string
Reason for the Error
X$KCVFH returned the specified code in the HXERR column when it was queried for the specified datafile.
Solution
Ensure the datafile exists and is readable. Using a newer release of Recovery Manager may return a more meaningful error message. If you have no newer version of Recovery Manager, contact Oracle Support Services.