This is a common problem with the Mavica FD95. There is a little switch in the drive slot to sense the write protect tab on the disk.
If you hold open the drive door without a disk in, you should see this switch where the write protect tab goes. Try operating the switch with a matchstick a few dozen times to attemp to clean the contacts. If that doesn't work then Very carefully let a drop of switch cleaner run into the switch and try operating it a few times then let it dry. Failing that you might want to open the camera to get to the terminals on the switch and test it with a multimeter.
If the switch is faulty and a replacement is not availble then you could just short(or disconnect) it to fool the drive into thinking any disk is writable.
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