Okay, so, here we go.
I managed to get it working with the help of stardock's own bagginz (or more accurately, he got it to work with me only providing the occasional nuisance

).
First and foremost, the "download and archive" option is having a problem with restoring. They are working on the issue.
The straight install shouldn’t be having a problem, but one could arise if you’ve switched between download servers – this appears to be the case for me.
Anyhow, the good news is that either way, there appears to be a workaround. Your downloaded archive needs to be from RC1 in order for this to work (probably – you could still try it regardless).
Here’s what I did…
· I extracted the “Multimedia_1.0.004_02.18.2003.zip” file using winzip (in other words, with stardock central closed). Make sure you check the box to “use folder names” when you extract. Extract to the \sdcentral\temp directory. Winzip may give you a crc error – it did for me – follow the prompts to continue on with the extraction. What you’re basically doing is taking the archive and putting it in the standard install folder. That way, you won’t have to download the entire thing all over again.
· Okay, once that’s done, your \sdcentral\temp folder should be fairly large (as much as 366MB). Now open up stardock central again and this time choose to do a standard install of the multimedia i.e. not a download and archive. Your download should begin again, though hopefully it will only be for 20-30 MBs at most.
· Once the download is complete, extraction should begin. At this point you’ll either successfully install the multimedia or you’ll get another “deleted file” error. If you get an error, simply start the install again. Repeat the process. It took me 4 errors (about 30-40 minutes and 36 MBs) to succeed.
You see, what it’s doing here is basically downloading only the files that it sees are necessary. Because you unzipped your archive into the temp folder, it doesn’t need to redownload everything. Little by little – literally file-by-file – it’s replacing the files that are causing these issues.
Did that make any sense? I can clarify if need be.