I SOLVED IT! Well at least for my end, hopefully this will work for you as well...
Windows7 64x and Backburner 2013
What I did:
First, Do a search for "backburner.xml". Mine was found on C:\Users\Username\AppData\Local\backburner
Second, Identify your MAC address. This can easily be done by viewing your "Network and Sharing Center", Click on the Connections link. The default is "Local Area Connection". You should see your Local Area Connection Status. Click on "Details." Your MAC address is your Physical Address line. EXAMPLE: 00-11-22-33-8D-F4 or something. Copy this address. (If you can't find it just search the internet how to get your MAC address.
Third, Open your backburner.xml file.
Fourth, Search for the string:
<ServerMAC>
It should be under the AppDetails Header.
Fifth, Make sure the ServerMAC address is the same as yours. If not, Paste your MAC address in this line. Should look something like this <ServerMAC>00-11-22-33-8D-F4</ServerMAC>
Save your XML file (backup your original if you have doubts).
Now the server.exe in backburner should work. If it doesn't EMAIL me and we'll discuss more options. Teriander@gmail.com
Good luck!