i have N900,and working perfectly but it is still give me option to unlock the operator lock. i dont know why, and who cares when every thing is fine. as far as i think operator lock in setting does not mean anything.

about your problem i also had some problem like you when i reflashed it. what i did i install uk image on my Indian n900 that made my sim not working. so i went back to India ver. and everything is fine now so may be your firmware is wrong ( i may be wrong) i tried global firmware also but same problem was there.