Why Can't I get a For loop working

procedure TMainForm.CdrButtonOKClick(Sender: TObject);
var
i : integer;
j : integer;
k : pchar;
begin
Assignfile(CdrText, CdrImportEdit.Text);
Reset(CdrText);
while not EOF(CdrText) do begin
ReadLn (CdrText, Buffer1);
ExtVar := PhoneNum(buffer1);
for i = strlen(Pchar(ExtVar)) downto 1 do
begin
areacode := copy(ExtVAr, 0,i) : string;
mySQLCollexClient.Query.PrepareTask (Pchar(SELECT * FROM stdcodes
WHERE areacode = '+areacode,nil,nil,AnyThreadedError;
SQLClient.Execute;
j := mySQLCollexClient.Query.DataCount;
SQLClient.Query.Clear;
if j > 0 then break;
end;
begin
mySQLCollexClient.Query.PrepareTask (Pchar(SELECT * FROM stdcodes
WHERE areacode = '+areacode,nil,nil, AnyThreadedError;
SQLClient.Execute;
k := mySQLCollexClient.Query.Data;
SQLClient.Query.Clear;
end;
edit1.Text := (ExtVar);
end;
CloseFile(CdrText);
end;