One is that maybe you don't have many stones inside of you.
I don't know what is in Andreas' protocol, (maybe some of the things i am about to mention... to be sure i need to check it out) but if you do have more stones and they are not releasing, 3 things i can think of that could possibly help are:
1. "zapping" (for a week or longer) and/or other parasite cleansing treatments (for 3 weeks or longer) leading up to the olive oil.
2. Massaging the Liver/gall bladder. With fingers or perhaps even with a big vibrating massager. Most especially the night you are to ingest the olive oil... but more days leading up to it would almost assuredly be even better.
3. Warm/hot Castor oil packs (or at least hot water packs) applied to the liver/gallbladder region. Again most especially the night of the olive oil.