https://www.ikmultimedia.com/faq/index.php?id=1239
A successful (default) install/configuration of the IKM products (especially for those of us with the Total Studio MAX 3.5 bundle) will have 2 paths set up so that the ST4 application finds all the content:
Use the Browse button and select the location where you have installed your SampleTank 4 sounds, then use the Browse button again to select your SampleTank 3 (Miroslav Philharmonik 2 or Syntronik) sound library. Notice these are installed to separate locations (Miroslav Philharmonik 2 and Syntronik will be installed to your SampleTank 3 folder).
I didn't realize that some of the VI's (Miroslav, Syntronik) get filed under a folder structure separate from ST4's content, even though ST4 is going to ultimately play/reference them.
Just pointing this out, since it seems a little unusual...