I had this bug too. The Windows computer doesn't detect automatically the filesystem problem when the Nokia is plugged. So, i had manually launch the filesystem fix tool (i used chkdsk from command line).

In my case, i filmed with my Nokia this week. I received a call just after i finished recording my video (and was switched to the phone app). When i had to "restart" the video record application but the video was gone and i didn't without having a chance to save it. It seems that i simply lost it without being able to do anything... It is as if a video is recorded to a temporary place and the users must tell to save it if he wants it to be included in the media library.