anyone seen this error before or can enlighten me?
looking up the error numbers jsut confused me more.

In RMAN I issued: backup database plus archivelog;

channel ORA_DISK_1: starting piece 1 at 22-AUG-03
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 08/22/2003 17:07:34
ORA-19502: write error on file "4ceve9st_1_1", blockno 67969 (blocksize=8192)
ORA-27063: skgfospo: number of bytes read/written is incorrect
Additional information: 311296
Additional information: 1048576
ORA-19502 write error on file "string", blockno string (blocksize=string)

Cause: Write error on output file.

Action: Check the file.