The schwarszchild radius of an electron=1.353*10^-57m, and to work out the volume of a particle assuming it is spherical is 4/3*pi*radius^3 so the volume of an electron at its schwarzchild radius is 4/3*pi*1.353*10^-57^3 = 0!?!?!!! WHAT DOES THIS MEAN :S
I'd say it means you need to learn about operator precedence so that you don't confuse (10^-57)^3 with 10^-57^3 = 10^-185193, causing an arithmetic underflow on your calculator.
May I suggest it's because the volume in cubic meters in less than 10^-99, hence your calculator figures this is as good as zero. Fair enough wouldn't you say!
Anyways, applying the concept of Schwarzchild radius to an electron seems pointless. EDIT: It appears it's not entirely pointless. There's even a wikipedia article about it.