Attached is a link that directs you to an open letter of repentance from a woman who formerly promoted the teachings of Henry Blackaby and Beth Moore. Her letter and the links she provides explains better than I can why she is concerned with their teachings and particularly their teachings about contemplative prayer.
Once you are on her blog, you can see some follow-up posts as well as read comments from those in support and against her view.
One of our responsibilities as a Christian is to be Bereans…search the Scripture to see whether what is being taught is actually true or not.
I encourage each one of us to be a Berean.