io is not defined

There was a suggestion here: https://github.com/btford/angular-socket-io/issues/77
- make sure you have socket.io client library: bower install socket.io-client --save

This didn't fix my problem with this same error.
- including in index.html:
script src="lib/angular-socket-io/socket.js"
- in app.js
angular.module('starter', ['ionic', 'starter.controllers', 'starter.services', 'starter.directives', 'btford.socket-io'])
- in services.js

.factory('seatStatusSocket',function(socketFactory){
var myIoSocket = io.connect(porturl); // io is not defined here, suddenly.
- It was working before, using a remote copy of the lib. When this error started, I changed index.html to link a local copy, as this remote version also received a Bad Gateway error (now fine, but still socket io is not defined as above).
- removed: script src="http://chat.socket.io/socket.io/socket.io.js"
- versions

socket.io@1.3.7 node_modules/socket.io
node --version
v0.12.7