How to Insert two queries in a single workbook in BI 7 ?

Hi,

I am trying to insert two queries in a single workbook. The queries are of Accounts Receivable.I have inserted one query in a workbook , but am not able to proceed to inserting the second query. In BEx analyzer, in design mode , using analysis grid , i tried inserting the second query but when saving and running, i am getting message " Variables are present, change their values " . should i maintain same variables for two queries ? i am stuck up. please explain me as how can this be done.

Roja.