512MB MMC card set read only state?

Hi,

Please help me, I'm running out of options...

I took photos with my Minolta G400 digital camera to 512Mb MMC card and
suddenly it said "SD error" and camera shut power off. G400 didn't read the
card at all. The card has been working fine the last few months.

I switched the card in my pc card reader. With windows 2000 pc, I could
transfer all old pictures, but all new pictures, taken today, were
corrupted. When I try to format the card it does not succeed, and I can't
transfer any data to the card either.

Then I tried to use Linux and mount the card, but still no success. Linux
says that the card is read only when I try to copy data to it.

I know that mmc cards (and SD card also) contains controller and memory
chip. The controller contains security registers where the card can be
write
protected etc. It seems that my mmc card controller has switched read only
bit on. In mmc and SD card specifications say that there are one command
"forced erase", that reset the card controller and erases the whole memory,
and after that the card would be usable again (it resets forgotten password
also). But the problem is that I don't know how to give that command to the
card, because apparently the normal format does not do it.

I would be very happy if someone could help me to open the card because it
cost over 60 euros and I dont want to spent more before I know all options.

Br. Pekka