Hello, i have this code who ive been using whitout any problems. and then suddenly at says acces violation at address 004b84 in module

"SecurityScreensaver.exe" when i trie to save a tstringlist to a file.

this is how the code looks

procedure TForm7.Button8Click(Sender: TObject);
var s : tstringlist;
begin
savedialog1.Title := 'Save image list to file (PS. Remember to add the extension name (etc. *.sss) to the end of the file';

// Only allow existing files to be selected
savedialog1.Options := [ofFileMustExist];

// Allow only *.bmp *.jpeg/jpg *.ico
savedialog1.Filter := 'All Supportet files|*.Txt; *.SSS|Text files|*.txt|Security Screen Saver File|*.SSS';

// Select All supportet formats
savedialog1.FilterIndex := 3;

// Display the open file dialog
if savedialog1.Execute then
begin
S := TStringList.Create;
for i := 0 to ListView1.Items.Count do
begin
S.Add(ListView1.Items[i].Caption); {This is where the error occurs}
end;
S.SaveToFile(savedialog1.FileName);
S.Free;
multipleimages := true;
multipleimagesdes := savedialog1.FileName
end
else
begin
multipleimages := false;
multipleimagesdes := 'None';
end;
end;

Any help would be appreciated,

Best Regards,
Darkyere