String parameter problem

hello, I got a problem in iBatis, i hope somebody could help me...
i hit problem when i pass in a parameter which the data type is string, and the field length in database is 19 char. But,it throws exception because the returned object is null. and then i try to change the WHERE clause condition,to based on other field which the data type is number,and it works...
i want to know what is the problem,is the string value too long or what?

below is my code example :

<select id="selectAccountById" parameterClass="Account" resultClass="Account">
    select
      PX_IR025_PAN as pan,
      F9_IR025_CRN as CRN,
      FX_IR025_EMB_NAME as name,
      FX_IR025_CRD_PGM as crdPgm,
      FX_IR025_UPD_UID as updId
    from IR025
    where PX_IR025_PAN = #pan#  
</select>


in java:

Account acc = new Account();

acc.setpan("1234567890123456");

acc = (Account) sqlMapper.queryForObject("selectAccountById", acc);   //(Note : return null)
System.out.println("  " + acc.getname());


Thanks before for your help....