I cannot explain why the dll does not load on some systems but I one thing I found when investigating is that at some point yesterday while developing a different plugin (the centroid plugin for complex objects) VS restarted due to an error. When this happened some of the settings of the projects were not saved so VS was not compiling the plugin to where I normally package them. Meaning it is entirely possible that what I put in the .zip file was a version that had not been tested. (I hate that about VS that some settings are not saved until the solution is closed - I have multiple projects in that same solution).
Anyways. I added more error handling and a few minor tweaks/improvements like making the version number reflect in the file info page and some general code cleanup.
As always use at your own risk. I have tried to make sure it is functioning as is should, but let's face it you are the testers

If you encounter error please let me know. It should work on Win7 (that is what I am testing using today) and that is nothing to stop it from working on Win8.
This was developed with the developement release, not the stable release.