Raisins are very bad for your dog, the cashwes should be ok, but I would still suggest taking your dog to the vet if you fed him a lot of raisins. Raisins and grapes are actually worse for dogs than chocolate. I am sure your dog will be fine, but to be on the safe side take them to the vet.
Not all dogs have a sensitivity. I have a client who feeds her dogs chocolate covered raisins everyday for 5 years or so as a treat. They say raw onions are bad too... Really, your Dog should be eating nothing but a good quality dog food. Like Evo, Taste of the Wild, blackwood, or Prisms. Most dogs are allergic to corn whet and soy, which dog food makers but in the food as fillers. Even Science Diet and Iams is crap now that They were bought out by a huge corporation. Don't let people give you too much trouble, they probably feed their dog Purina which will give them cancer! Or worse... Canned food that will rot their teeth out.