The datacab3 problem may
be just another symptom of a cd-rom drive that can't read the JK2 cd due to copy protection. I'm guessing that it might be the reason because I've seen this happen whenever a new game comes out with copy protection.
I've also experienced the problem myself. I have an excellent Aopen 52X CD-ROM drive that can't handle any game that is copy-protected.
Also keep in mind that when this happens people may get all sorts of different error messages like "invalid 32-bit application" or "file missing" or system hangs or a cd-rom drive that just keeps on spinning or just gives up after a while.
When Rune came out and so many people couldn't play it, some people recommended getting the CDSpeed utility from Nero at www.ahead.de
(click on English then you'll see the CDSpeed banner at the top) to slow down the speed of their CD-ROM drive to get the game to install. I tried it once and didn't get it to work but didn't work that hard at it.
The only guaranteed way I know of to install the game is to get a very new namebrand (Pioneer, Lite-On) DVD-ROM or CD-RW drive that can "handle" the cd's copy protection. I've been fairly lucky with my Lite-On 12x burner. For those games that it will install but then not play, I've relied on NoCD patches. I've considered getting a Lite-On 16x DVD-ROM drive for $48 just so I wouldn't have to deal with this problem but have managed to get by without it so far. Sorry about the bleak solution but if your cd drive truly can't read the CD, you're out of luck.