I tried your file and it worked fine from my side. I can confirm that it is neither a problem with Appium nor with your configurations.
For some unknown reason your keyboard might be inserting the wrong characters, so please download the following file node.txt133), change the extension from .txt to .json (as the website here forbids uploading .json files) and try again.
Also to make sure that there is no syntax error with your json file, you can use the following website: http://www.jsoneditoronline.org/39