Steven Zahm@ Nash
Ok, that Uncaught TypeError error is the cause. Any script that tries to run after that error can not be run.
Farbtastic is the old (legacy) color picker WordPress use to use once upon a time. Another plugin or the theme must be using it without making sure they limit its usage to there own admin pages, a best practice to that prevents theses types of conflicts.
My suggestion… try deactivating all other plugins. Does the export work now? If it does not, then the theme is the cause. If it does work, then one of the plugins are the cause. Activate each plugin one at a time. After you activate a plugin, try to do an export. If you can, the plugin is not the cause. If you can not, then that plugin is causing the issue. Do this one at a time until you identify the bad plugin.
Hope this helps, let me know.