What program did you use to capture/save that mp4? Did you make two passes - one at 1080 and the other at 720?
Go to OPTIONS | MEDIA tab and UNcheck this box. Audio should then be okay.

As for video freezing at higher resolutions, test the latest 64-bit version. For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest. Retain your old install file and registration info.