Excel 2000

Really simple data sheet: list of names with homerooms
Lookup table: list of homerooms with teachers. (named "Range")

=VLOOKUP(E2,Range,2)

Some of the cells return the correct name, others #N/A.

As far as I can tell they are all formatted exactly the same; I've tried
several different formatting options. The correct ones stay the same; the no
data ones do not change either.

Any ideas?