Can some one point out to me the error in this sql statement?

Code:
SELECT CommTypes.Description
FROM CommTypes LEFT JOIN 
   (SELECT * 
    FROM IntroducerBasis 
    WHERE IntroducerBasis.IntroducerCode ='AG'
         AND IntroducerBasis.BasisNumber=1) 
       AS Intro
    ON CommTypes.ID = Intro.CommTypeID;
The error highlights the subsequent SELECT statement as the source...