C:\Program Files\Java\jdk1.8.0_65\binC:\Program Files\Protege_4.3\bin directory, replace Apache Felix’s felix.jar with the latest one from the Felix website (StackOverflow Q&A)The Excel plug-in (also called Spreadsheet importer) is named org.clinicalescience.csv.jar. The Download link on the Protege wiki is broken.
However, the plug-in is available from http://www.antepedia.com/Detail/p/co-ode-owl-plugins.html (click See more releases (2)). Copy the JAR file to C:\Program Files\Protege_4.3\plugins and restart Protege.
Go to Window | Tabs and click Spreadsheet Importer.
An example CSV can be found here.