SVP working, but not all the times.

I don't understand why, but I got SVP installed and already had MPC-HC + K-Lite Codec Pack. So I got MPC running with MADvr and SVP is working, but not every time. Some videos files will work, but some does not. Sometimes two different video will have the same container (like MKV) but one will work, but the other will not (with the no active playback message on SVP). Any idea why?

Thanks for the possible help!