report viewer doesn't work only for particular report on server

Question

All report works fine when run on VS,but when i tried after published, i got this error. this error only comes out in one of the 4 reports(others work fine),in which confuse me even more

error

i've convert all input to string

input row is

row.companyName = company.name;  
row.companyType = company.companyTypeName;  
row.companyFields = company.BusinessFields;  
row.companyAddress = company.companyAddress;  
row.companyDetail =company.CompanyDetail;  
row.productGroup= product.ProductGroupName;  
row.productType= product.ProductTypeName;  
row.productCode= product.ProductCode;  
row.orderPrice = Math.Round(order.TotalValue).ToString("#,0.00");  
row.orderPriceWord =     OrderManager.NumberToWords(Convert.ToInt64(Math.Round(order.TotalValue)));  
row.fee= order.feeRate.ToString();  
row.feeWord= OrderManager.NumberToWords(Convert.ToInt64(Math.Round(order.feeRate)));  
row.age= order.itemAge.ToString();  
row.ageWord= OrderManager.NumberToWords(order.itemAge);  
row.feeAmount= Math.Round(order.feeAmount).ToString("#,0.00");  
row.feeAmountWord= OrderManager.NumberToWords(Convert.ToInt64(Math.Round(order.feeAmount)));  
row.customerName= aspnet.FullName;  
row.customerAddress= customer.Address;  
row.reportDate= DateTime.Now.ToString("dd MMMM yyyy");  
row.dueDate= order.dueDate.ToString("dd MMMM yyyy");  
row.yearNow= DateTime.Now.Year.ToString();