error in function!!

Hi,

i have a problem with the following sentence:

CREATE OR REPLACE FUNCTION tschema.sp_actualizar_contacto(p_idpers text,
p_nombre text,
p_apellido text,
p_titulo text,
p_fecnac text,
p_codedociv integer,
p_sexo text,
p_codpais integer,
p_pw text,
p_empr text,
p_cargo text,
p_pwempr text,
p_aniv text,
p_prof text,
p_trab text,
p_fecgen text,
p_fecing text,
p_fuente text,
p_codupload integer,
cli_codigo integer ) RETURNS text as '

DECLARE
c_codigo integer;
c_sinc varchar;
c_idpers ALIAS for $1;
c_nombre ALIAS for $2;
c_apellido ALIAS for $3;
c_titulo ALIAS for $4;
c_fecnac ALIAS for $5;
c_codedociv ALIAS for $6;
c_sexo ALIAS for $7;
c_codpais ALIAS for $8;
c_pw ALIAS for $9;
c_empr ALIAS for $10;
c_cargo ALIAS for $11;
c_pwempr ALIAS for $12;
c_aniv ALIAS for $13;
c_prof ALIAS for $14;
c_trab ALIAS for $15;
c_fecgen ALIAS for $16;
c_fecing ALIAS for $17;
c_fuente ALIAS for $18;
c_codupload ALIAS for $19;
cli_Codigo ALIAS for $20;
BEGIN
select nextval(''seq_tbu_contacto_cont_codigo'') into c_codigo;

Insert into tbu_contacto (cont_codigo, cont_idpers,cont_nombre,cont_apellido,cont_titulo,cont_fecnac,cont_codedociv,cont_sexo,cont_codpais,cont_pw,cont_empr,cont_cargo,cont_pwempr,cont_aniv,cont_prof,cont_trab,cont_fecgen,cont_fecing,cont_fuente,cont_sinc,cont_codupload) values (c_codigo,c_idpers,c_nombre,c_apellido,c_titulo,to_timestamp(c_fecnac,''YYYY-mm-dd HH:MM:SS''),c_codedociv,c_sexo,1,c_pw,c_empr,c_cargo,c_pwempr,c_aniv,c_prof,c_trab,to_timestamp(c_fecgen,''YYYY-mm-dd HH:MM:SS''),to_timestamp(CURRENT_TIMESTAMP,''YYYY-mm-dd HH:MM:SS'') ,c_fuente,''S'',c_codupload);

return ''OK:''||c_codigo;

END;
' LANGUAGE 'plpgsql'

this is the error in pgadmin III on windows (postgresql 8.0):

ERROR: function tschema.sp_actualizar_contacto(integer, "unknown", "unknown", "unknown", "unknown", "unknown", "unknown", integer, "unknown", "unknown", "unknown", "unknown", "unknown", "unknown", "unknown", "unknown", "unknown", "unknown", "unknown", integer, integer) does not exist
HINT: No function matches the given name and argument types. You may need to add explicit type casts.

I need to know if the "insert sentence" was sucesfull, how do i do?

help me with this please,

thanks!!