=AND($A2=$C2,$B2<>$D2)
or when you have your datarange defined as table (and column headers are without spaces)
=AND([@ID1]=[@ID2],[@Course1]<>[@Course2])
entered into ERROR column and copied down, returns TRUE/FALSE in ERROR column. It is enough to use ERROR column for filtering/order, but of-course you can use this formula as condition in IF() function to return anything different like "error"/"".