Palm Treo 750 SD Card Problems

I have a Sandisk 1 gig Mini SD card in the Treo. Recently it stopped storing
images and video from the phone's camera. I had to change the settings so that
it saved them to main memory.

When I took a photo the unit would pop up an error message "cannot open file"
during the file saving process. It worked fine when the setting was swapped to
main memory.

I had a look in the card via the WinMob File Explorer. Now, it has a number of
folders with various files, one called My Pictures which has a couple of images
in it, and some folders with spreadsheets and other documents.

However, there was one folder, DCIM where the camera is supposed to save its
files. It had photos in it already but I could not see them. And the phone
couldn't save the images to that folder.

Today, after a month or so of trying to figure this out, when I had the time to
sit down and fiddle with it, I renamed the DCIM folder to something else. I then
created a new DCIM folder and set the camera to save images to the storage card.
Now it can save images and video to the memory card. I then transfered the files
across from main memory back to the card, freeing up around 15 megs.

I can see the photos in the new DCIM folder. However, the old one, renamed
DCIM2, is still blank and nothing can be written to it.

I thought that maybe the folder was somehow changed to "read only" or hidden or
something like that, but there is no option anywhere in WindowsMob6 that allows
me to change the storage card's attribs.

Any thoughts on why this might have occured? Or has anyone heard of this one
before?