However, your first issue is likely user error and would need more info. Please feel free to take it over to the forum. It is likely you don't have the right codec in the mp4 file (it needs to be h.264). The mp4 file extension doesn't imply any particular file format (codec), this is a common point of confusion. Flash/HTML5 needs h.264.
I have fixed your second issue in #1400.
However, your first issue is likely user error and would need more info. Please feel free to take it over to the forum. It is likely you don't have the right codec in the mp4 file (it needs to be h.264). The mp4 file extension doesn't imply any particular file format (codec), this is a common point of confusion. Flash/HTML5 needs h.264.