Downloaded 'shadow of the comet'

extracted it with winrar and got a whole lot of strange img, sub, and cue files. Looked it up, extracted again using isopen, got a hole bunch of more normal looking files

won't run directly from vista so tried it with dosbox
when I run the installation file i get: installation path must be c:\infogram\shadow\cd
and then it exits

found this problem in a german forum but the translation is terrible and can't make out how they got around it
What do I do?

Any help would be much appreciated me and my severely limited computer knowledge invested far too much time trying to get this game sorted for it not to work