String / Variable Problem - Dynamic Table Name - MS SQL

String / Variable Problem - Dynamic Table Name - MS SQL: "DECLARE
@AddressID int,
@ProgClient (varchar(10),
@Table varchar(10)
,@sql nvarchar(1000)

SET @Table = 'i2b_' + @ProgClient + '_contact'

SET @sql='SET @AddressID = (SELECT AddressID FROM '+@Table+' WHERE ContactID
= @ContactID)'
exec sp_executesql @sql,N'@ContactID int, @AddressID int
output',@ContactID,@AddressID output

select @AddressID"