Well, I think few animals can't cope with at least shallow water. But there still are...
Common Peafowl
Fennec Fox
(I'm one! And I swim just fine!)
Red Panda
Small Primates (Chimpanzee, Ring-Tailed Lemur, Orangutan, Crested Gibbon, Gelada, Barbary Macaque)
Animals That Can't Cope With Deep Water:
Above Animals
Most Ungulates (except for the African Buffalo, Wildebeest, White Rhinoceros, Black Rhinoceros, Hippopotamus, Pygmy Hippopotamus, Baird's Tapir)
Red Kangaroo
Gorilla
I'm not sure about koalas... I've heard they don't swim but I once saw one do it...?