He seems to be getting his roman numerals messed up.
V7 is the dominant chord of a key, diatonically speaking. V is a roman numeral for 5, because it's built on the 5th degree of a scale. A V7/V is basically just (In C major) A G7(G,B,E,F) To a G, (G,B,E) which makes a small difference, depending on how it's used. No D's anywhere, unless you meant II7/V, which is a nice cadence.
Anyways, The rest of quickfinger's stuff's solid, but mostly irrelevant to pop music, sadly. Good for classical stuff though.
