dossrv doesnt know about users, bill trog is some dummy name and probably some inside joke.
the /adm/users file is for fossil/kfs/cwfs and unrelated to your problem. usbfat: mounts the device with -c, so creating files in the root should work on this part. i'v seen this before and it might be a bug in dossrv itself on fat32 partitions. it only happend on the filesystem root directory. run a filesystem check on the drive with some other operating system. once followed the exact codepath for that error, but can't remember. reformating the drive (with FAT16) fixed the problem. -- cinap