When I do :
cordova plugin add https://github.com/phonegap/phonegap-facebook-plugin.git
I get the error :
Error: Variable(s
I am using DevExtreme - maybe it run in anothers plataforms - and I had the same problem. I late to resolve because when I changed my config.xml to set APP_ID and APP_NAME and after create .zip to use phonegap's build, this params(APP_ID and APP_NAME) disappeared of config.xml. The solution was edit config.xml after create .zip, not before like I did.
Obs: While I was researching about this, I saw many developers having the same problem. To resolve it, they fixed your .xml with this test http://www.w3schools.com/xml/xml_validator.asp
I hope this help.