"=vlookup(A2,'Sheet2'!A:A,false)",

This formula has incomplete parameters. The Excel 2000 help file (F1)
defines VLOOKUP funcation as:

VLOOKUP(lookup_value,table_array,col_index_num,ran ge_lookup)

You are placing a boolean value (e.g. FALSE) where an integer value
needs to be. To wit, you are placing your desired "range_lookup"
optional value in the required "col_index_num" parameter. While FALSE
can loosely be defined as zero (0) and TRUE as anything NOT FALSE, it
generally isn't good practice to substitute a boolean for an integer
and especially in your case as there is no ordinal column number zero
(0) in a range. In your example perhaps a more appropriate formula
would be:

=VLOOKUP(A2,'Sheet2'!A:A,1,FALSE)

HTHs