The issue is that the NPAPI plugins don't work on Chrome version 42 and higher.
A fix for this has been found:
How to temporarily enable NPAPI plugins
If you must use a NPAPI plugin, there’s a temporary workaround that will work until Chrome version 45 is released later in 2015:
- In the address bar at the top of the screen, type chrome://flags/#enable-npapi
- In the window that opens, click the link that says Enable under the Enable NPAPI flag:
- Enable NPAPI Flag Screenshot
- In the bottom left corner of the page, click the Relaunch Now button.
After the release of Chrome version 45, you’ll need to use an alternate web browser to load content that requires a NPAPI plugin.
More information can be found here: https://support.google.com/chrome/answer/6213033