Element SADDR1 Is Undefined In SESSION

Hi there, I am sorry to be abother but I was wondering if there was someone to tell me what I am doing wrong. Here is my statement. I am getting the following error.

Element SADDR1 is undefined in SESSION

SELECT [clv].[dbo].[UNIT].[HMY] ,[clv].[dbo].[UNITTYPE].[sdesc] ,[clv].[dbo].[UNIT].[SRENT]
,[clv].[dbo].[UNIT].[dtAvailable] , clv.dbo.property.saddr1, clv.dbo.unit.scode
FROM [clv].[dbo].[UNIT] inner join clv.dbo.PROPERTY on clv.dbo.property.hmy =
clv.dbo.unit.hproperty inner join clv.dbo.UNITTYPE on clv.dbo.UNITTYPE.hmy = clv.dbo.unit.hunittype
WHERE saddr1 = #session.saddr1# and ( hunittype='2' OR (hunittype='3') OR (hunittype='4')
OR (hunittype='5') OR (hunittype='6') OR (hunittype='7') OR (hunittype='8') OR
(hunittype='25') OR (hunittype='26') OR (hunittype='27') OR (hunittype='28') OR
(hunittype='29') OR (hunittype='30') OR (hunittype='31') OR (hunittype='32') OR
(hunittype='33') OR (hunittype='34') OR (hunittype='35') OR (hunittype='36') OR
(hunittype='37') OR (hunittype='39') OR (hunittype='41') OR (hunittype='42') OR
(hunittype='44') OR (hunittype='45') OR (hunittype='46') OR (hunittype='47') OR
(hunittype='48') OR (hunittype='49') OR (hunittype='50')

Thanks