I suspect that the tags might have been slightly bogus, and that replacing them with newer versions fixed them. I can't be sure, however.
The point is that there's nothing specific in emplode for point versions of ID3v2.
Is this with the emplode that shipped with the Rio Central, or have you tried using the latest car player beta version of emplode?
If you've still got one of these files, I'd appreciate it if you could send it to me, so that I can take a look at it.