problem with creating/dropping tables and plpgsql ?

I'm pretty new to postgresql.. I'm using a fresh compile/install of postgresql 7.1.2 without any special options.. but
here'smy problem:
 

semantic=# create temp table ttmptable(lookup_id int, rating int);
CREATE
semantic=# SELECT doEverythingTemp(20706,2507);doeverythingtemp 
------------------               1
(1 row)
semantic=# DROP table ttmptable;
DROP
semantic=# create temp table ttmptable(lookup_id int, rating int);
CREATE
semantic=# SELECT doEverythingTemp(20706,2507);
ERROR:  Relation 4348389 does not exist

--- schema --

CREATE FUNCTION doEverythingTemp(int,int) RETURNS int AS '
DECLARE rrec RECORD; userid int; lookupid int; rrating int; ruser int;
BEGIN userid := $1; lookupid := $2; FOR rrec IN SELECT webuser_id,rating FROM rating WHERE webuser_id!=userid AND
lookup_id=lookupid;    rrating:=rrec.rating;     ruser:=rrec.webuser_id;     INSERT INTO ttmptable SELECT
lookup_id,rrating*ratingFROM rating WHERE webuser_id=ruser AND lookup_id!=lookupid; END LOOP; RETURN 1;
 
END;' LANGUAGE 'plpgsql'

Table "rating"Attribute  |  Type   |                         Modifier                         
-------------+---------+----------------------------------------------------------
webuser_id  | integer | not null default '0'
category_id | integer | not null default '0'
lookup_id   | integer | not null default '0'
rating      | integer | not null default '0'
rating_id   | integer | not null default nextval('"rating_rating_id_seq"'::text)
Indices: rating_category_id_idx,        rating_lookup_id_idx,        rating_rating_id_key,
rating_webuser_id_idx


I've tried regular tables, creating the table from within the function, and a few other things.. no luck.  Does anyone
haveANY idea how I can either redesign this query or make the create/drop thing work properly?
 

Thanks,
(::) Bob Ippolito