new rule syntax?

I have two tables defined as:
checks       (ckid                int NOT null PRIMARY KEY,        payto               text,        notes
text,       ckdate              date,        printed             int  default 0,        tdate               timestamp
notnull)
 
checkitems       (item                int not null,        ckid                int NOT null references checks,
itemtype           int not null,        amt                 numeric(7,3),        primary key         (item, ckid))
 

in previous versions (<8.1) the following rule declaration seemed to 
work finecreate rule checks_d0 as    on delete to checks       do delete from checkitems          where ckid =
checks.ckid;
in 8.1.2 I get

ERROR: missing FROM-clause entry from table "checks"

any idea?

-- 
Arthur R. Van Hook     Mayor 
The City of Lake Lotawana

hook@lake-lotawana.mo.us

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