Arduino mini requires uploading on every power up?
There was a defective bootloader that shipped on some Arduino devices which caused the symptom you describe. See:

http://forum.arduino.cc/index.php?topic=51172.0

http://forum.arduino.cc/index.php?topic=74090.0

If that's the case, your options are to re-write the bootloader yourself (if you have the capability) or return to the manufacturer.