I had the same experience, except a different error message. At home I have a very old pc about....... 8yrs old where I would type college papers, I would also use the newer computers at the campus to edit my work. After awhile when I used my floppy to change my work from the newer to older computers...... the newer computers will display an error message saying they cannot open my file and that my floppy must be reformatted. I could see the file but not open it as you are saying.
When I put the floppy in to the old pc at home it open the files just fine. Anyway it happen a second time, at campus. I could see the file but not open it though, I was able to drag it to a usb flash drive which then allowed me to open the file?
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I dunno does that help? I usually see problems saving info on my cdrws between pc and mac computers, eventually it gets corrupted. I got a Corsair 128MB flash drive from newegg which was much much cheaper that the ones the school sells. Better quality too. I never experience any problems switching from various computers with those flash memory. I still prefer cdrws though, they are about a buck each and holds a good amount of data.