Hallo Hein,
Yeah.... You do have a serious reason to be concerned. It seems your PSR has a big problem and she can let you down at any time.
I'm not sure how the OS is stored : In flash rom or battery powered RAM. But the fact you have to reload the OS again is a 'bad' sign.
I would advise you to visit your dealer/repair center as soon as possible, because there seems to be a hardware faillure. I hope the error can be reproduced so the engineers have something to diagnose.
kind regards,
Roel