Can't mount FAT

[Douglas Royds]

I can't mount any FAT partitions - neither my shared FAT partition nor 
my USB flash-drive:

$sudo mount -t vfat /dev/sda1 usb
mount: wrong fs type, bad option, bad superblock on /dev/sda1,
       or too many mounted file systems
This install just doesn't seem to know anything about fat. Is there some 
module that I need?

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