Firstly, what values do you have for F1 and H1?
Secondly, what values do you have for A2, A3, and so on?
Thirdly, you say you got 0 and #NAME! in columns B and C respectively after
copying down; what results did you have in B2 and C2 *before* you copied
down the column?
Fourthly, are you sure that column C is returning #NAME! and not #NUM! ?
If it's giving #NAME! then it sounds as if you've mistyped something. In
general it's safest not to retype, but instead it's better to copy the
formula from where it's been given to you, and paste into the formula bar of
the cell you're using.
The words Mean in E1 and Std.Dev in G1 are merely labels for presentation,
and to tell the user what to put into F1 and H1, so they shouldn't afect the
functioning of the formulae.