it's your lucky day. Android phones happen to be my other hobbie (mercedes being the first) I'm not sure exactly what kind of wallpaper you are trying to find, but you can easily pull a picture off your computer and put it on your microSD card. i think the site wont work because 1. android lacks flash support, OR 2. the android browser doesn't support the format that the website is in
try downloading Opera mini 5 from the Android market and seeing if the site works on it.
also, have you tried finding a wallpaper application in the Android market? there is bound to be at least 1 app. that will give you a wallpaper you will enjoy.
if all else fails, take a picture of your beloved Mercedes and set it as your wallpaper
