I have posted a update to the plugin which upgrades all the dependencies to the latest versions and changes the way the files are generated. This might fix some of the issues people are having with the longer runs.
Please download the latest version by clicking the “Download” menu option above.
Update: 8/8/2014 – Published to the Chrome Web Store
Update: 3/Mar/2016 – Project code is now up at https://github.com/jkili/nike-gpx for those that want to fix any issues