Good afternoon! I was having the same problem and could not find the solution, using windows 10 and isadora 3.08 usb version, I just downloaded the plugin again, but it gives me a new error when loading, (DLL Load Error = 0000007E). Always when opening isadora. and it keeps telling me that the plugin cannot be loaded. I have tried deleting the isadora preferences, reinstalling isadora again, with both kinect sdks, and even with another computer with isadora 3.07.
I believe I have worked out the problem. When I tested the plugin on a fresh copy of Windows, I got the DLL error too. (I previously had tested on my development machine, which has extra files that allowed the plugin to run without error.)
In any case, a new version has been uploaded as of 9:26 am Berlin time (3:26am EDT time) on April 24th. 2021.
Please go to the OpenNI Tracker add on page, download the plugin package again (openni-tracker-win-v0.9.8b4.zip), and install the plugins as directed in the READ ME file. (I have not changed the version number, but the contents of the file are different.)
When dragging the three plugins to the shortcut, please make sure to replace the existing plugins as directed in the READ ME.
Report back here or in the ticket you opened if you have any trouble. I'm sorry for the inconvenience.