I see the problem, even though the size is correct, it's 75x75, it has too many pictures and the overall size of 26kb is too much. You have 7 pictures, and it's really hard to get 7 pictures in an avatar. If you check out this page:
http://www.yorkietalk.com/forums/pro...?do=editavatar, it tell you what the maximum size of your avatar can be, you have pixel restrictions, which you have met, and KB which you have gone over. You can take out one or two pictures and see if it works.