DATABASE ERROR

I have entered new client, did direct invoice, received and allocated payment. When I want to print statement for client on outstanding amount I get the following message if I do not select Yes to "show also allocated". If I select Yes, the statement disappears.

DATABASE ERROR : No transactions were returned
error code : 1305
error message : FUNCTION aquilla1_Front.ABS does not exist
sql that failed was : SELECT 0_debtor_trans.*, (0_debtor_trans.ov_amount + 0_debtor_trans.ov_gst + 0_debtor_trans.ov_freight + 0_debtor_trans.ov_freight_tax + 0_debtor_trans.ov_discount) AS TotalAmount, 0_debtor_trans.alloc AS Allocated, ((0_debtor_trans.type = 10) AND 0_debtor_trans.due_date < '2013-08-14') AS OverDue FROM 0_debtor_trans WHERE 0_debtor_trans.tran_date <= '2013-08-14' AND 0_debtor_trans.debtor_no = '48' AND 0_debtor_trans.type <> 13 AND ABS(0_debtor_trans.ov_amount + 0_debtor_trans.ov_gst + 0_debtor_trans.ov_freight + 0_debtor_trans.ov_freight_tax + 0_debtor_trans.ov_discount) > 1e-6 AND ABS (ABS(0_debtor_trans.ov_amount + 0_debtor_trans.ov_gst + 0_debtor_trans.ov_freight + 0_debtor_trans.ov_freight_tax + 0_debtor_trans.ov_discount) - alloc) > 1e-6 ORDER BY 0_debtor_trans.tran_date

If I try and email the statement it gives me a message:

You have no email selected for this customer, but I just emailed the invoice to the customer.

any assistance would e valued.

regards

Wynand