It sounds like your Reference Materials folder is not being read correctly. Could you please check that the Reference Materials path is set correctly in iolite's Preferences (in the Paths section). When you installed iolite, you would have been asked if you want to create an iolite folder in your Documents folder. In that iolite folder, there should be a folder of reference materials. That's the folder iolite should be loading, and that is what is set in iolite's Preferences.
If you have any questions about any of the above, or if that doesn't work, please let me know.