Myes , these are install shield archives, but you are right, data2.cab seems to be broken. Its a bit big to open with , say wordpad to see what's in it. Mostlikely images going by the size ( gp's) There were also 2 setup.exe's init (?), one's flagged by the antivirus.
Are these archives? I don't recall where this is used.
Then i remember Gex posted his version on the hawsk forum a while ago, it was of a different structure ( called MnS.Exe) but ofcourse that link has gone dead. I wonder if anyone ever downloaded that one. Might have a working data2.cab in it.