Error creating function in DB2 with params

I have a problem with a function in db2

The function finds a record, and returns a number according to whether the first and second recorded by a user

The query within the function is this

 SELECT
 CASE 
 WHEN NUM IN (1,2) THEN 5
 ELSE 2.58
 END AS VAL 
 FROM (
 select  ROW_NUMBER() OVER() AS NUM ,s.POLLIFE  
 from LQD943DTA.CAQRTRML8 c 
 INNER JOIN LSMODXTA.SCSRET s ON c.MCCNTR = s.POLLIFE 
 WHERE s.NOEMP = ( SELECT NOEMP FROM LSMODDTA.LOLLM04 WHERE POLLIFE = '0010111003')
 ) AS T WHERE POLLIFE = '0010111003'

And works perfect

I create the function with this code

CREATE FUNCTION LIBWEB.BNOWPAPOL(POL CHAR)
RETURNS DECIMAL(7,2)
LANGUAGE SQL
NOT DETERMINISTIC

 READS SQL DATA
RETURN (

 SELECT
 CASE 
 WHEN NUM IN (1,2) THEN 5
 ELSE 2.58
 END AS VAL 
 FROM (
 select  ROW_NUMBER() OVER() AS NUM ,s.POLLIFE  
 from LQD943DTA.CAQRTRML8 c 
 INNER JOIN LSMODXTA.SCSRET s ON c.MCCNTR = s.POLLIFE 
 WHERE s.NOEMP = ( SELECT NOEMP FROM LSMODDTA.LOLLM04 WHERE POLLIFE = POL)
 ) AS T WHERE POLLIFE = POL
)

The command runs executed properly

WARNING: 17:55:40 [CREATE - 0 row(s), 0.439 secs] Command processed. No rows were affected

When I want execute the query a get a error

SELECT LIBWEB.BNOWPAPOL('0010111003') FROM DATAS.DUMMY -- dummy has only one row

I get

[Error Code: -204, SQL State: 42704] [SQL0204] BNOWPAPOL in LIBWEB type *N not found.

I detect, when I remove the parameter the function works fine!

With this code

CREATE FUNCTION LIBWEB.BNOWPAPOL()
RETURNS DECIMAL(7,2)
LANGUAGE SQL
NOT DETERMINISTIC

 READS SQL DATA
RETURN (

 SELECT
 CASE 
 WHEN NUM IN (1,2) THEN 5
 ELSE 2.58
 END AS VAL 
 FROM (
 select  ROW_NUMBER() OVER() AS NUM ,s.POLLIFE  
 from LQD943DTA.CAQRTRML8 c 
 INNER JOIN LSMODXTA.SCSRET s ON c.MCCNTR = s.POLLIFE 
 WHERE s.NOEMP = ( SELECT NOEMP FROM LSMODDTA.LOLLM04 WHERE POLLIFE = '0010111003')
 ) AS T WHERE POLLIFE = '0010111003'
)

Why??