costvalue

this is costvalue methos but compile time show error undefine cost value

please tell me solution

display SalesName costvalue(arg)

{

CustInvoicejour ct;

select * from ct

where ct.AccountNum == custInvoiceJour_1.OrderAccount;

return ct.Name;

}

This is Another Method Opning Blance same error in this methods

display AmountMST openingBalances()

{

return openingBalances;

}