Instant JChem databases are only available for import if the Instant JChem application and the Spotfire/JChem4XCL integration are running. This is described in the Instant Jchem User Guide in detail, but the most important steps are mentioned here as well.
Start Instant JChem and click the Projects label on the left side.
Select an ijc-project and right-click it.
Click the Start Spotfire/JChem4XCL integration button.
JChem for Excel communicates through web requests with the Instant JChem application.
The information including chemical structures is collected into OData objects and sent in XML files.