Sony Ericsson W910I Help!!?

[Darkkingofgames]

I Want to get a games and screen savers for my Sony Ericsson W910I, But when im trying to convert it through Transfer Cable, I have downloaded ".Jar" games, and i want to give them to my W910I, to "Others" Folder, and some strange error appears (Like this extension is not working with this Mobile Phone), and it doesn't work! Help me, the same with screensavers.