You've come to the right place to get help with error 15242, tra1120.
As stated in the error, the FCS file of your QuickBooks is damaged, and we need to fix that to let you download updates. The FCS (File Copy Service) file on the other hand is responsible for initiating and downloading updates in QuickBooks.
To fix this, you'll want to repair the program, but please back up your files first to make sure you got a copy of them.
Select Start and then Control Panel. (In Windows 8/8.1: From the Start menu, open Search and type Control Panel. From the results, select Control Panel.)
Select Programs and Features.
If necessary, choose Uninstall a program.
(If you don't see these options, select Programs, then Program Features.)
Select QuickBooks in the list of programs and choose Uninstall/Change.
Select Continue, then Next.
Select Repair then Next. Wait for the Repair to complete.