I pored through the Ubuntu forum threads linked to in the bug report, and someone else already noted that editing a file with OpenOffice seemed to cause the problem. Why no one bothered to say that in the actual bug report, I don't know. I'm going to add a comment to that effect myself. And you are right about it being that particular bug--I tested the same files in Excel 2003, and got the "disk full" message mentioned by the original poster.
