536811 Immediate Task - Support in Online

I've a Web Based software, developed in Adobe and Back End is SQL. Now a days i've a problem in that application. That is i unable to process more particulars in One Step. The Error is : "Object reference not set to an instance of an object" The software is one year old and the current data base size is 80 MB with 3 Lack data's. Its a billing software. I can able to prepare few items in one stroke. But when the number of items increases the Invoice is not saving and Returning some errors. Kindly see the attached screen shot. The software is developed in ADOBE FLEX, .Net, SQL. I need this to be done very quickly through online. waiting for a talented person. Karthik:)