I had a huge problem with scratchbox... and i was trying for normal debian.. so i cant help there.

for your grep problem I imagine that is because maemo uses busybox for most of its core apps which may include grep... you'll have to look into getting the full grep compiled in either the scratchbox or the maemo.. or maybe u can try and copy the grep binary from maemo's environment to the tablet?

those would be my suggestions...sorry cant be more helpful.