In the past, that means at least until 10.2.x it used to be a bit clumsy to set the archivelog deletion policy to “applied on standby” on both primary and standby database. It involved setting an underscore parameter, as per Metalink Note 728053.1 “Configure RMAN to purge archivelogs after applied on standby”. For reference, the parameter was _log_deletion_policy, and you’d have to bounce the database for it to take effect.
SQL> alter system set "_log_deletion_policy"='ALL' scope=spfile;
Only then could you avoid the error message.Now with 11g that’s a lot easier.