I too am having problems trying to take a HD video that I shot and burn to a standard dvd. Playmemories brings up a message that the first time converting a HD video to standard, I must download additional software. The download manager 1402b ends up with a message that the URL for the "add on software" is expired.
Maybe I don't understand what I am doing. I thought that I could take an AVCHD file and that the software would convert it to a lower quality format that would burn to a standard dvd.
I can take the same video file and burn to a dvd, but it takes 4 disks to hold the whole video, and I have to chop it up to fit.
I saw this same problem in an earlier thread and I tried all of the fixes in that thread to no avail. I did not see whether the issue was ever resolved.