It helps to know that the font/encoding plays a part. That definitely narrows it down a lot better. Because you can copy/paste the text directly into mIRC and it shows fine regardless of encoding (Japanese vs Western), it still points to the DLL being at least partially the cause. It may also be possible that the text you're trying to display actually has another character that you're not seeing... one that Japanese encoding can deal with, but Western cannot. If you were to edit the ID3 for that song (make a backup of the song first so we still have the original to test with) and paste in what you see in the channel then try displaying it in the Western encoded channel, it might work because you might not end up pasting in a "bad" character. I've come across certain MP3s that had corrupted ID3 tags that mIRC didn't like and just editing the ID3 with what appeared to be the same information fixed the problem. Just to note, a better way than copy/paste of that would be to get someone to type the song name using the Japanese characters and then copy that so that you can't accidentally copy some character that isn't visible from the original.
Just to check, see if you can display the title in the Western encoded channel using mIRC's built in identifiers like I mentioned earlier. If it crashes then too, then it's likely a problem with the ID3 tag. If it doesn't, then it's likely a problem with how the DLL sends that particular tag to mIRC. Remember to display the title tag rather than the filename.
