No probs mate.
Actually I notice there's a mistake with the formula. The part here ...
=IF(COUNTIF(DataSheet!$A$1:$A$100,$A2)>=COLUMNS($A:A),INDEX(DataSheet!$B$1:$B$100,SMALL(IF(DataSheet!$A$1:$A$100=$A2,ROW($A$2:$A$101),""),COLUMNS($A:A))),"") should be ...
=IF(COUNTIF(DataSheet!$A$1:$A$100,$A2)>=COLUMNS($A:A),INDEX(DataSheet!$B$1:$B$100,SMALL(IF(DataSheet!$A$1:$A$100=$A2,ROW($A$1:$A$100),""),COLUMNS($A:A))),"")
NB: it's an array formula so you have to press Ctrl Shift Enter when you've finished editing it - you tell if you did it right because it will have curly braces around the formula like this
{=IF(COUNTIF(DataSheet!$A$1:$A$100,$A2)>=COLUMNS($A:A),INDEX(DataSheet!$B$1:$B$100,SMALL(IF(DataSheet!$A$1:$A$100=$A2,ROW($A$1:$A$100),""),COLUMNS($A:A))),"")}
(You mustn't enter the curly braces manually)