Yes, it isn't a real file, just a pointer to a block device. I've got that too, it points to a file in the /proc directory which is dynamically generated by the kernel. Maybe it is related to a change made in Titan's kernel (the power kernel). I wouldn't worry about it though. So are you still unable to delete that directory? Maybe you should try doing the filesystem check on the N900 if Windows didn't fix anything (I promise it won't take as long as the Windows scan did). Have you tried deleting your problem folder when it is mounted on your Windows PC?