It has been confirmed: Skittles are NOT vegetarian.

The reason for this is that they contain gelatin, observe:

Gelatin (also gelatine , from French gélatine) is a translucent, colourless, brittle, nearly tasteless solid substance, extracted from the collagen inside animals' connective tissue. It has been commonly used in food, pharmaceutical, photography, and cosmetic manufacturing. Substances containing gelatin or functioning in a similar way are called gelatinous. Gelatin is an irreversibly hydrolyzed form of collagen. Gelatin has an E number of E441.

Now, this is what animals' connective tissue is:

Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue.) It is largely a category of exclusion rather than one with a precise definition, but all or most tissues in this category are similarly:

Involved in structure and support.
Derived from mesoderm, usually.
Characterized largely by the traits of non-living tissue.
Blood, cartilage, and bone are usually considered connective tissue, but because they differ so substantially from the other tissues in this class, the phrase "connective tissue proper" is commonly used to exclude those three. There is also variation in the classification of embryonic connective tissues; on this page they will be treated as a third and separate category.

Pretty fuckin disgusting huh? HOWEVER, the european recipe DOES NOT CONTAIN GELATIN! But it still has shellac, which is believed as a substance in insect wings.