[GAP Forum] Permutizer Condition

[lopo apelo kosho]

Dear Friends,
I am writing a GAP code to check on the normalizer condition. Recall that a finite group G satisfies the  normalizer condition iff for each proper subgroup H of G H is Proper in its normalizer. 
I have constructed the following code: 

#################
 IsNormalizerGroup:=function(g) local s,i;
> if IsAbelian(g) then return true;
> fi;
> if IsPGroup(g) then return true;
> fi;
> s:=Difference(Subgroups(g),[g]);
> for i in [1..Size(g)] do
return false;
> if Order(Normalizer(g,s[i]))=Order(s[i]) then
> return false;
> fi;
> od;
> return true;
> end;
function( g ) ... end
#################
but when I checked for the direct product group D:= C3X Q8
I get the following error: 


Error, List Element: <list>[20] must have an assigned value in
  if Order( Normalizer( g, s[i] ) ) = Order( s[i] ) then
    return false;
fi; at *stdin*:2805 called from
<function "IsD3Group">( <arguments> )
 called from read-eval loop at *stdin*:2809
you can 'return;' after assigning a value
################################################

I still do not know how to fix it
Any suggestions please. 
Thank you.