It worked just fine on the bookshop's exhibition computer in China so I must be missing some kind of software. Would any of you know what it could be, and where I could find it?
The CDs are called "zhi hui gu shi da quan", published by www.tofo.net, if that's any help.
Thank you in advance!
ETA: problem solved, thanks to daemon_will. The solution was to save the unreadable files as .htm files, then open them with a web browser and fiddle with the encodings. Thank you!