Can it be that mystcraft is bugged? no matter what i do i always get unstable ages.... even tried copying a cheat sheat http://i.imgur.com/JjokY4u.png and still always unstable x.x i just want a desert single biome miningworld :<
Cheat sheets are almost guaranteed to not work as they probably haven't been updated. A number of things have changed ( such as bright lighting now adds instability ), so people are needing to relearn how to make stable ages.
People have reported stable random worlds, so it should be possible.
You might want to keep an eye on the mystcraft forums: http://binarymage.com/forum/viewforum.php?f=9