Realdrums are included
Check the location of the drive assigned to realtracks and realdrums

Audio Settings - Song Generation

Sometimes, when using the external drive for realtracks and drums, the drive letter changes on the computer itself and needs to be changed in RB.
If you plug it in today, it may be K: and tomorrow it may be O:
So browse to the location and re-tell RB where they are.
If you leave the drive plugged in it likely won't change again, but if you move it, it might.

I do not work here, but the benefits are still awesome
Make your sound your own!