I noticed your post and saw no had responded. I have not used the ballistics calculator off the home page, but went over there to look to see if I could answer your question.
It looks like you just need to follow the directions for a log in name and password specific to the ballistic calculator. Being logged into the LRH site does not log you into the calculator. The "gear shop" works the same way. Hope this helps. Maybe someone else will see your post that can be more specific.