RMAN level 0 complains it can't find archivelogs

I'm putting together an RMAN strategy on 10g under Linux, temporarily doing everything to disk while we prove the principles. I want to restart  a fresh cycle of backups with a brand new full backup (10.2 on Linux). I scheduled a full backup from EM checking the "Use as the base of an incremental backup strategy" box and it generated the following command:

backup incremental level 0 cumulative device type disk tag ...

The job failed because a week-old archive log is no longer on disk (we'd had several successful incrementals since then), which surprised me given the box I'd checked. What do I have to do differently so it will just start with a clean slate and not try to find archivelogs? Why does EM generate the keyword "cumulative"? - it seems redundant in the context of a level 0... ?

Thanks

Andy Received on Tue Mar 27 2007 - 05:43:54 CDT