Over cooked rice cakes?

I’ve made rice cakes for tteokbokki three times now. I don’t have access to Korean grocers in my area so I decided to make my own rice flour. I use a moderately sized food processor to grind up my soaked rice. Every time I make the rice cakes they turn out crumbly and dry, I’ve been using Maangchi’s microwave rice cake recipe and I even checked at 20 second intervals. Is my rice flour not ground all the way? am I not using enough water? am I using too MUCH water? I just don’t know where its going wrong.