OK Sorry about that. Another plugin updated the json dlls and the mpwifi one was looking for the old version of this dll. It is hard to keep track of all the plugins sometimes, especially ones I don't normally use myself.
For a quick fix, please replace the MpWifi.dll with the attached. The file should be saved to your VC folder\plugins\MpWifi
It is also important to note that sometimes when you download a dll from a web page, Windows will block it. To avoid this, after you download the dll file into the correct folder, you should right-click it, and select properties. Then if you see a button at the bottom that says "Unblock" you should click it. IF you don't see the button then you probably don't need to do anything.
I will include this new version in the next release of VC. Thanks for pointing it out to us.
[30-Dec-2015 -- dll attachment deleted. This is an old dll. Users should not be downloading old dll's. As soon as new dll's are created, they become the standard plugin dll in the next release of VoxCommando.]