When I am updating AVG antivirus free edition in my system it shows a error every time : " A .bin file is missing ".. what is this meant for.. can anyone help me

On the AVG user forum there's a thread that indicates the problem is probably a corrupt or incomplete update on the publisher's server and that the solution will require further updating by the application publisher's staff. I'm betting the same message, but the user interface indicates that the Link Scanner and Resident Shield are still operating.

Once again try to update and if still same as above. Try to uninstall and download it from avg.com and install it again...
Check the avg update service is started or not
Start > run > type services.msc then select the avg update service and click on the start to run services.