DATABASE CRASH

[nacho]

hi.
Why when execute a function the database crash?
an example;
 
CREATE FUNCTION DAMEESTADOOBRA(IDOBRA CHAR(35)) RETURNS CHAR(35) AS
  VAR 
   ESTADOOBRA VARCHAR(35);
    
  SELECT IDESTADOOBRA FROM KERSAN.CONTROLOBRAS 
   WHERE ID = :idobra;
  FETCH INTO :estadoobra;
 
  RETURN ESTADOOBRA;
  
 
execute this query "select dameestadoobra(id) from controlobras" and
then database crash.
 
use maxdb 7.5.00.15, Windows Xp or Windows 2000 
 
 
thanks