Ok, I fixed that script error in my copy. I was confused because there is an error in the documentation page
All the examples at the top of the page show "enable" rather than "true", but examples toward the bottom show "true".
At your request I created a setting, you can add this to your user config and put in the url for your local script.
<add key="GoogleAnalyticsScriptOverrideUrl" value="" />
These changes will be in svn trunk by tonight.