OK,
I just tried this. I went to the GSI site and downloaded the latest bundle of the legacy plugins here:
http://www.genuinesoundware.com/?a=showproduct&b=37I then unzipped and copied the entire folder maintaining the structure, etc. to my x86 VST folder.
I launched SONAR and did a fresh VST folder scan.
It does seem that all of the instruments are working as expected. There are what Guido calls donationware "nag" screens but without any limitations.
Try scanning your VST again but make sure all of the plugins folder structures are intact as when you first downloaded them.
Hope you can get them to work as they are still very fun and sound great.