How do I introduce table name into my stored procedure as a parameter

I have a c# application running against a postgresql database.

I want to use a delete statement in my stored procedure where
the table name i am deleting from is sent in as parameter This will allow me use the
same script for different tables.

To test the concept,  I did a stored procedure with the table name 'locations ' explicitly stated
(see procedure below ) and it worked
1. The script that worked stating table name  as 'locations'

[]CREATE OR REPLACE FUNCTION public.spalltables_delete(
IN companycodex text,
IN tablex  text,
IN idx integer,
IN deletetypex text)
RETURNS void AS
$BODY$
BEGIN
UPDATE locations
SET
validrecordyn = 'N'
where  id = idx and companycode = companycodex and  'DM' = deletetypex;
IF NOT FOUND THEN
delete from locations where  id = idx and companycode = companycodex and 'DP' = deletetypex;
END IF;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION public.spalltables_delete(text,text,integer,text)
  OWNER TO postgres;[/code]

-------------------------------
When I now brought in the table name  'locations 'with a parameter tablex (see below)
i got the error attached

2. The script with table name as a  parameter

[][CREATE OR REPLACE FUNCTION public.spalltables_delete(
IN companycodex text,
IN tablex  text,
IN idx integer,
IN deletetypex text)
RETURNS void AS
$BODY$
BEGIN
UPDATE tablex
SET
validrecordyn = 'N'
where  id = idx and companycode = companycodex and  'DM' = deletetypex;
IF NOT FOUND THEN
delete from tablex where  id = idx and companycode = companycodex and 'DP' = deletetypex;
END IF;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION public.spalltables_delete(text,text,integer,text)
  OWNER TO postgres;[/code]
 
The script above compiles properly as a stored procedure but give the error below during execution.

3. Error Page


How can i bring in table name as parameter  and get it to work in my stored procedure

Olukay