If you got constipation don't do the shakes. Some people according to Chinese medicine have a "dry" body and get constipated, also according to Ayurveda certain body types. You can try something like Oxypowder , Mag07, Colosan.
Check the Colon Cleanse forum.
You can also get too much Sugar from dried fruit, change to vegetables.
BTW it is normal not to get solids after the flush from using the ES (magnesium sulfate). If you feel better after the flush, the flush worked, you don't have to see "stones" you still get detoxified.