SQL error at or before <EMPTY> ?

[tcurrier]

Hello,

Can anyone help me figure out what the SQL error below is caused by ?
Thanks for any help ....

SELECT CONCAT_KEY,                                     
  COUNT(*)                                             
FROM (SELECT DIST_NUMBER||AGT_NUMBER||AGT_INDEX        
  AS CONCAT_KEY                                        
  FROM H2591DB.TCSAU_EVMA                              
  WHERE STATE = '20'                                   
    AND GENERAL_STATUS = '1'                           
    AND REASON_GENERAL IN ('A','B')                    
    AND DIST_NUMBER = 'ERP')                           
  GROUP BY CONCAT_KEY;                 

QUERY MESSAGES:
SQL error at or before <EMPTY> (line 9, position 29).

[tcurrier]

FYI : I received an answer from another forum:

SELECT CONCAT_KEY,                                     
  COUNT(*)                                             
FROM (SELECT DIST_NUMBER||AGT_NUMBER||AGT_INDEX        
  AS CONCAT_KEY                                        
  FROM H2591DB.TCSAU_EVMA                              
  WHERE STATE = '20'                                   
    AND GENERAL_STATUS = '1'                           
    AND REASON_GENERAL IN ('A','B')                    
    AND DIST_NUMBER = 'ERP') X                                                
  GROUP BY CONCAT_KEY;          

(I needed an 'X' at the end of line 9)