Guessing here, but because of your equi-joins, you are coming back with a NULL record. If it's not that, then there's no username which matches the one you passed in.
Deconstructing the SQL statement, and adding back in one table at a time will help you figure out which of the 2 above scenarios are possible. If it's the former (equi-joins), at first you'll see records returned until you finally add the table and it's equi-join which foils the request. If it's the latter (no user name), then you'll know it immediately when you run
Code:
SELECT fu.user_name FROM
fnd_user fu
WHERE (fu.user_name = 'SMITHD');
Then, you can decide what to do, use outer-joins, a union all, etc.
-=cf