For those that made the changes I’ve described here I want to suggest a better method. So go back to webBrowser.isRunning and take out the changes that you made. If you’ve forgotten what the changes were just delete the 2 places that you inserted the string() verb.
The change is better made in sys.appIsRunning() and would look like this.

on appIsRunning ([string(id)]) {
	kernel (sys.appisrunning)}

The reason is that changing here will correct the problem all over the root and not just in the webBrowser.isRunning script.
Jake has made this correction in the root updates so you won’t need to do it.
You will still need to add ‘sfri’ to the list of OS X browsers at webBrowser.supportedBrowsers.