Function and trigger problem

I use the following code to create a function:

create function employee_stats_update() returns int4as 'insert into employee_stats values ( new.employee_name); select
1as ignore_this'
 
language 'plpgsql';


Then I create the following trigger:

create trigger update_employee_statsbefore insert on employee_master for each row execute procedure
employee_stats_update();

This is what I get back when I try to create the trigger:

ERROR:  CreateTrigger: function employee_stats_update () does not exist

Adam