strange behavior of plpgsql function

Hi all,
I am facing a small but strange problem when using a plpgsql function as
below.

CREATE OR REPLACE FUNCTION fnvs.docrelatedassociatedetails(p_docid integer,
p_addtype smallint, p_associateid integer, OUT docid integer, OUT
associateid integer, OUT addressline1 varchar,OUT addressline2 varchar,OUT
addressline3 varchar,OUT city varchar,OUT state varchar,OUT country
varchar,OUT postalcode varchar, OUT addtype smallint)
RETURNS SETOF record AS
$BODY$
begin
return query SELECT docid, associateid, addressline1, addressline2,
addressline3, city, state, country, postalcode, addtype from
docrelatedassociates where docid=p_docid and addtype=p_addtype;
return;
end;
$BODY$
LANGUAGE 'plpgsql' VOLATILE SECURITY DEFINER
COST 1
ROWS 10;

Above function was first written to return a set of records as same as a
table, but it didn't worked. Then I written above code and it works but does
written any data. When the same function is written using SQL as language it
works well. even from above function, it I call the newly written sql
langauge function it returns data correctly. What will be the problem.

CREATE OR REPLACE FUNCTION software.docrelatedassociatedetails(p_docid
integer, p_addtype smallint, p_associateid integer, OUT docid integer, OUT
associateid integer, OUT addressline1 varchar,OUT addressline2 varchar,OUT
addressline3 varchar,OUT city varchar,OUT state varchar,OUT country
varchar,OUT postalcode varchar, OUT addtype smallint)
RETURNS SETOF record AS
$BODY$
SELECT docid, associateid, addressline1, addressline2, addressline3,
city, state, country, postalcode, addtype from docrelatedassociates where
docid=$1 and addtype=$2::smallint;
$BODY$
LANGUAGE 'sql' VOLATILE SECURITY DEFINER
COST 1
ROWS 10;

Above function was created few days ago and then I changed the structure of
the table which is used to return setof records. After that this problem is
occuring.

Thanks,

CPK