备份恢复的错误ORA-01180: can not create datafile 1

ORACLE备份成功，但是在恢复时却报不能创建DATAFILE1

creating datafile fno=1 name=/oracle/oradata/XXX/system01.dbf
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of restore command at 08/16/2011 17:37:27
ORA-01180: can not create datafile 1
ORA-01110: data file 1: '/oracle/oradata/XXX/system01.dbf'

权限啥的都没有问题。