dodgepong, you are a genius! I changed all the settings, and BAM, it worked. Tracked back which one it was, and it was the "Custom x264 parameters:". I had entered in "crf=0 vbv-maxrate=0 vbv-bufsize=0" as recommended by a gaming website, and this text appears to be the problem. Vegas & Premier can now see the videos correctly.
Thanks a bunch for your help!