Alright, it should still be possible to work around this. Put 2DSaver's 3dsx file under the "3ds" directory on your SD, and name it something like "2dsaver.3dsx". After that, place the homebrew launcher's 3dsx on the root of the SD with the name "boot.3dsx". I just tested this myself, so I know the HB loader should at least launch without an error. Once you're in the HB menu, try launching 2DSaver. Since you bought this pre-hacked, it may also be a good idea to ensure you're on the Latest Luma and HB loader versions.