The getPlus(R) error is a security issue related to Adobe download manager.
You need stop the getPlus(R) service from the task manager. Then delete the folder named NOS in the program files folder. After that uninstall the current version and download the latest version and install. You need to restart the computer once after uninstalling the previous version of flash player. Also make sure the getPlus(R) service is not running in the task manager.
If you have troubles with GetPlus, don't use it. Uninstall it; do not just delete any folders.
You can download the offline installers (without GetPlus):