How do I fix this problem?
By a proper installation of the library. The tar.gz you probably downloaded from code.google.com contains a HiH folder. Inside this folder you have a HIH61XX and a HIH61XXCommander folder. Copy these two folders into the "libraries" folder in your sketchbook folder (the location of which depends on your operating system, on Linux it's named "sketchbook" and directly in your home directory). Then quit the IDE and start it again.