If you are using shell extension for APK Easy Tool and you want to update, you must unregister and uninstall it first

Open APK Easy Tool. Go to options -> General and click Uninstall Context menu integration. It will ask you for admin rights
Windows 8/10: Open Task Manager and restart all explorer.exe processes
Windows 7: Open Task Manager, end task all explorer.exe processes and run new task explorer.exe

Then you can replace or delete AETShellExt.dll and don't forget SharpShell.dll ServerRegistrationManager.exe too