Accelerometer, Orientation failded to start : Unknown error

I am having **Motorola Milestone xt720 (android 2.1)** in which orientation doesn't work automatically but if i enabled it and if the screen is in landscape mode then it continuously remain in landscape..so have to disable it manually to get back into normal mode. Checking using **AndroSensor** it reports : Accelerometer: Failed to start :Unknown error Orientation : Failed to start :Unknow error So is it a hardware problem or some application problem ?