The file that's missing is one of the files in the RTP, so it's either not installed correctly or not being read. Strange that this error would pop up if the old version of the game worked normally.
The 3rd option on the Troubleshooting page has a link to a zip of the RTP files that you can unzip and paste into your ゆめ2っき\ folder, which might fix this if you've already installed the RTP correctly. :)