"a friend of yours" and "your friend" mean the same thing. Note that it's "your friend", not "yours friend". Also, note the difference between "planning" (which means "preparing for", as in "I'm planning a party" or "My brother plans to go to college") and "planing" (which means "using a tool called a 'plane' to shave down and straighten a piece of wood").

Yes they are. The first one is correct. The second one is wrong! It's that simple.