this might be a ls version problem you are using 0.24.7 beta3. it might work better on a indie 0.24.6 build but i have never used nanostep.

it could also be a problem in theme design/modules configs.
try commenting out loadmodule lines one at a time(remeber to save before recycling) in the themes step.rc
until it recycles without crashing. then you found the problem module. look at its config and make changes.