In order to enable the context menu items, Rightload would have to register a shell extension with Windows. This would not only make changes to the system, but also cause problems if you want to remove the flash drive containing Rightload from the computer again.
Since this would defeat the whole point of a portable application, it will unfortunately not be possible to enable the context menu. If you really want to do something like this, the only suggestion I could make is to put the installer on the drive, install Rightload where ever you need it, and then change the configuration directory to a folder on your flash drive. This would allow you to move your configuration between computers while still having the context menu.
Sorry!