The RemoteCommands endpoint should also be passed a MachineName on the QueryString:
http://www.mobileminerapp.com/#api{Root URL}/RemoteCommands?emailAddress={Email Address}&applicationKey={Application Key}&machineName={Machine Name}&apiKey={API Key}
Whoops, sorry! I think you should notify people of this Nate, I only just changed this the other day as the email you sent on the 5th said
"You should no longer send the MachineName as an argument in the URL query string. Instead you should provide the MachineName on the JSON object you are sending via HTTP POST."
In retrospect obviously this didn't apply to the commands - I'll fix ASAP!
Good call - I'll send out a note. The change was specifically about the "Statistics API" but, in hindsight, that's not super clear. The change is only for that specific endpoint.