Dear Junebug,
this is indeed a fault on our side.
1. the plug-in r42 was written ONLY for LS2000 on OSX - and we forgot to change the info text on the download page.
2. Although even this r42 plug-in may run on OS9 as well, it will lack the support for Nikon's ICE function!!
This means there is no sense in updating from your r27 (o.k.) version to a higher release with less features.
The good news: the follow up release will be supporting that ICE feature again on OS9 and only then you should consider to
update your SilverFast. However, the following LS2000 release for OS9 will NOT have any extraordinary new features whatsoever. The only purpose for this
update is that the next (hybrid) plug-in which is supposed to support the LS2000 on OSX will then open under OS9 as the usual (known) SilverFast as you have it with your r27 already.
In short: only because two SilverFasts for two operating systems are going to be merged into one SilverFast installer the release for SilverFast OS9 will change.