CommandText Issue - SQL Reporting Services

I'm having a ton of trouble with a dataset. It builds at design time,
but fails at runtime, saying:

---------------------------
Processing Errors
---------------------------
An error has occurred during report processing.
Cannot set the command text for data set 'ds_Legal_Entity'.
Error during processing of the CommandText expression of dataset
'ds_Legal_Entity'.
---------------------------
OK
---------------------------

Below is the CommandText for ds_Legal_Entity that gives me the error:

="SELECT DISTINCT dbo.t_d_legal_entity.legal_entity_desc FROM
dbo.t_d_legal_entity INNER JOIN dbo.t_f_month_summary ON
dbo.t_d_legal_entity.legal_entity_key =
dbo.t_f_month_summary.legal_entity_key WHERE
(dbo.t_f_month_summary.acctg_mth_key = " &
Parameters!acctg_mth_key.Value & ")" &
IIF(Parameters!BusUnitKey.Value = 0,""," AND
(dbo.t_f_month_summary.bus_unit_key = " & Parameters!BusUnitKey.Value &
")") & " ORDER BY dbo.t_d_business_unit.legal_entity_desc"


If I delete everything after " & Parameters!acctg_mth_key.Value & ")",
I won't get the error, so I assume that's where the problem lies. I
just need another pair of eyes to see it.

Thanks!
Mike