Union Of Queries Pls Help

Three sql statements whose result has to be unioned

SELECT
orders_recipients as Email
FROM vendors
where
vendorID in
(select Vendorid from Restaurants_VendorsAssoc where restaurantid = @resid)
union
SELECT str_eMail as EMail from tbl_contactmanager where (bit_shared =1) and int_restaurantId in (select restaurantid from users where userID in (select UserID2 from Users_Linked where UserID1 = @userid))
union
SELECT str_eMail as EMail from tbl_contactmanager where int_restaurantId = @resid

I am getting an error message as follows
The text, ntext, or image data type cannot be selected as DISTINCT.
pls help