How do you take Linux off of a hard drive?

If you want to make a file system on hda5, do this command:

mkfs -t vfat -c /dev/hda5
to make a fat32 filesystem in that partition.
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It responded with:
    Attempting to create a too large filesystem.

What the heck does that mean? Rather, how do I push my creation through the
seive (funnel)?