>When I use the dairy-free margarines the cookies come out like
>crispy crumbly...any ideas?

Are you using a spreadable margarine, or Sticks? Milk- full margarine
for baking is about 70-80% oil, Maybe the non-milk margarine has less
an oil concentration. Sometimes I'm able to substitute 3/4 cup oil
for the margarine called for- Sometimes I just have to try a
different recipe. I don't have much time to play around with recipes-
adding flour, etc, so can't help with that.....There's one oatmeal
cookie recipe that flattens out that I've dubbed oatmeal crisps and
crumbs- it spread out so much that there were holes between the
oatmeal flake areas.Ugh (translated as- I totally understand the
'crispy crumbly cookies').
Other suggestions-
Possibly chill the dough before baking
Add some Agar/ gelatin/ eggs if possible.
Bake lower temp/ longer, or higher temp/ shorter time so they can't spread out.