7 out of 10, and I'm demanding a recount on the German players question: Mark Schwarzer was born in Germany and I can think of one more conventionally correct answer than they claim. I won't put the names down so as not to give it away for anyone else attempting the quiz.
I've just looked again, and I misread their anwswers! I put 5 German players, and I thought they said it was 3. In fact they said it was 4. I was also wrong about Mark Schwarzer, but the German-born keeper I was thinking of is Maik Taylor. If you count him, plus Reither, Voltz, Reidle and Dirk Lehmann my 5 would be correct. Sadly, 'German-born' isn't the same as 'German', so I'll have to give them that one.