I cannot install a newer version of Scanner File Utility or update it. An error message tells me that Scanner File Utility is already running and that it should be closed before installation.

Scanner File Utility is running as a Windows service, you can see that in Processes of Windows Task Manager (search for 'nsCatCom.exe'). This will not happen when installed as an application. Go to Start/Programs/Scanner User Software and start the Scanner File Utility - an icon will come up in your system tray. Here you can stop and exit the program. After that you can install it again.