In going through the forums, I found at least two other bug reports of essentially the same behavior, but I wanted to ensure that I reported this as well. ( <a href="https://app.roll20.net/forum/post/527404/bug-tryin" rel="nofollow">https://app.roll20.net/forum/post/527404/bug-tryin</a>... and <a href="https://app.roll20.net/forum/post/569471/bug-error" rel="nofollow">https://app.roll20.net/forum/post/569471/bug-error</a>... I would like to use the API to create a new token from an image in my library. Then, I would like to modify that token in some way (change the size or position or whatever). The token is successfully created, but I get the following error when I then try to set a property on it: /home/symbly/www/d20-api-server/node_modules/firebase/lib/firebase-node.js:1 orts, require, module, __filename, __dirname) { function f(a){throw a;}var j=v ^ Error: Firebase.child failed: First argument must be a non-empty string and can't contain ".", "#", "$", "[", or "]". at Error () at Ha (/home/symbly/www/d20-api-server/node_modules/firebase/lib/firebase-node.js:12:204) at G.W.H (/home/symbly/www/d20-api-server/node_modules/firebase/lib/firebase-node.js:126:213) at TrackedObj._doSave ( This is a minimum working example that reproduces the error: on("ready", function(obj) { var curPageId = findObjs({_type: "campaign"})[0].get("playerpageid"); createObj("graphic", { _pageid: curPageId, layer: "map", name: "test", imgsrc: "url-of-your-preferred-image-goes-here", width: 80, height: 80 }); var newIcon = findObjs({_type: "graphic", _pageid: curPageId, name: "test"})[0]; log(newIcon); newIcon.set("width", 200); }); The icon is found, and its properties are printed to the console, but attempting to set a property generates the error above. I don't think it matters, but I am using Chrome Version 33.0.1750.154 m.