Welcome to CD Freaks.
Memorex is a highly questionable media & best to avoid.
What burner do you have, what other video/burning apps do you have installed (like
Nero for example) & what is the media code of the Memorex discs? This latter piece of info can be obtained using Nero's CD-DVD Speed with the disc info tab. This can be obtained
here if you don't already have it.
I'm concerned by the "DVD-R packet writing" line. This might suggest that you have something like Nero's InCD installed. Do you?