It all depends on your diet. If you have enough protein in you diet, then
protein powder would not be necessary. If not, you will not enjoy optimum results from your creatine usage. The two is not inter-dependent, but protein powder could help with the recovery process. But this goes for your diet in general (if you are
lifting weights) - if you do not consume enough proteins you will not recover (and grow) at an optimum level. See creatine as a performance enhancer and protein powder as a recovery aid.
So: yes & no.