I already know this issue: the DVD player reads fat32 drives only. That's why there are now USB drives formatted as fat32 (like the Verbatim 1.5 TB I bought recently - Samsung inside ), although a few years ago almost any usb drive was ntfs formatted.
I don't know any command or utility to convert ntfs into fat32 (with no file loss).
It read that "Partition magic" did that, however I don't know if it was a real filesystem conversion fith no file loss or just fat32 format. In any case, Partition magic is discontinued since last year.
I think the way is to backup the partition content, and use GParted to format the partition as fat32 (or delete the existing partition and create a new one with fat32 fileesystem). Then, you can transfer the files back to the new partition. GParted can make fat32 partitions of any size, instead of the 32GiB limit for win xp.
An alternative would be to buy a new fat32 usb drive (and keep the actual disk as a backup disk).
Another alternative, to buy a new ntfs drive, delete the partition and create a new fat32 one with GParted.
Potential problems:
file permissions can't be transfered, I think, because windows operating system doesn't support the same permission scheme as in ntfs.
ntfs supports UTF characters in file names, but fat32 doesn't.
I don't know if long file and folder names have the same limits under ntfs and under fat32. Short names are safer.
I read that some dvd players read short file names only.
fat32 doesn't support files bigger that 4GiB, I think. So, bigger files like some dvd iso couldn't be transfered in this drive.
*** It is highly recommended to backup any important files before doing resize/move operations. ***