problems restoring rman backup (RMAN-06026)

Hi,

We are having problems restoring rman backups. Sometimes. If a single backup is
made then restored it works. Subsequent (or possibly just older ones) fail.

We get an RMAN-06026 "some targets not found"

I've done an RMAN "list backupset" and, if I'm correctly interpreting the
output all the missing files are of the form EVENTn.DBF. Not all the files fail
just the older one (I've only got one example so far so this isn't definite).

The rman command looks like this

RMAN>         run { set until scn 545992;
2>             allocate channel ch1 type disk;
3>             allocate channel ch2 type disk;
4>             allocate channel ch3 type disk;
5>             restore database check readonly;
6>             recover database check readonly, delete archivelog;
7>             sql "alter database open resetlogs";
8>             }
9>         exit;

the restore fails.

--
Nick Keighley