A scary thought might be that data is being saved with different filesystems overlapping and a disaster is about to occur.
I would format the drive as FAT32 and use vfat not auto as the type in your fstab. As you are dual-booting, I would partition and format it from Windows, I have had the odd problem with using Linux fdisk to set up FAT partitions.
I have two hard drives, first holds 3 Windows partitions (C:, E: and F
and 7 Linux partitions, (boot1, boot2, root1, root2, home, swap and spare). The second disk is just a huge Windows FAT32 partition (D
which holds data. I divided the disk up using fdisk from Win98SE, then reformatted partitions as Linux using a Mandrake install disk, before installing Gentoo! (Partitioning was easier than it sounds!)