Hey Dean! Just came across an improvement. The php file is currently using the 'home' option to locate the files in the plugin directory. You probably want to use the 'siteurl' option instead, as the 'home' is the browser url and can be changed from the actual file location.
I JUST launched my site so I changed 'home' to be the root production url and not the development dir anymore, the plugin stopped working and I tracked it down to that issue. Changed the php to use siteurl instead and all is well again.
Check it out if youd like! http://whatthefestival.com . It is working great right now, we will see how it performs under a much higher load when we actually announce it in the morning. I have still noticed a few random Back button issues but I'm not too worried about it. and yes, I believe I've made all the changes in the latest version.
I will be sending you a donation for all your hard work and your great plugin next week. Thanks again!
- Matt D