I was annoyed by the errors and missing voice replay function in this release, so I tried copying the file from kanon, and to my great pleasure it worked. Thought I'd share it here to help out anyone else who might happen upon this post. Just drop koeicon.g00 in the g00 folder to say goodbye to that annoying error and have a functioning voice replay button.
However, it's probably best to go into the .ini and change
#KOEREPLAYICON.REPPOS = 540,50
to
#KOEREPLAYICON.REPPOS = 520,50
so that it's properly aligned and not awkwardly hanging off the text box
If anyone else has the correct file from Air though, that would probably be better. I could not track it down and figured just grabbing the one from the other game I already had on hand would be easier.
edit: The gao gao translation patch for the game that this release is using seems to be busted. Crashes and weird bugs all around. The winter confetti patch in my experience is both more stable and a better translation.