To get general ideas about AutoPlay in XP, see the MS article
http://msdn.microsoft.com/msdnmag/issue ... fault.aspx
Apparently it is enough to consider AutoPlay for your CD-ROM drive only (this is simpler, since your burner may have more handlers, and you usually forget to specify which drive has been tested!). You could uninstall EasyWriteReader to provide a cleaner testing environment, but it shouldn't matter, so I won't insist (you could do it later if everything else fails).
It won't hurt to re-check a couple of points.
1. My DVD Drive Properties | AutoPlay lists the following content types: Music files, Pictures, Video files, Mixed content, Music CD, DVD movie. For each content type, no action is selected, but "Prompt me each time to choose an action" is marked. Do you have the same types and actions?
2. When I insert an empty UDF 1.50 disc in my DVD-ROM drive, an Explorer window opens, showing a single (hidden) file "Non-Allocatable List" with size 0 KB at the root of the drive. For a CD-MRW disc, a similar window pops up without any file. Do you get the same windows?
3. When you say that AutoPlay doesn't work for the three disc copies, do you mean that the drive just spins up and then down immediately, and you don't get the "sniffing" window which should pop up when the disc is being scanned?
4. Have you tried to access the files on the three discs? E.g., double clicking on an .mpg file should probably call Windows Media Player, etc.
Well, if AutoPlay only fails on these three discs, with different media (CD-R/CD-RW) and formats (UDF 1.50/CD-MRW) but supposedly identical contents, then the failure should be due to the particular file types.
Assuming that sniffing inspects only file name extensions, such as .gif or .mpg (instead of examining each file to determine its type), you should check the file types on the troublesome discs relative to the file types on other discs for which AutoPlay works. Here I'm sharing your suspicion that maybe one or more file types cause AutoPlay failures.
To identify the culprit(s), starting with an empty InCD disc, you could copy successive file types from the troublesome disc until AutoPlay fails. Alternatively, it may be easier to delete files from an InCD disc until AutoPlay works.
Could you confirm that you have never meddled with AutoPlay via tweaking programs or registry hacks?