NIS 2011 Facebook Scan Never Completes

If I initiate a Facebook scan with Norton Internet Security 2011 (v18.0.6.29), a Facebook login page opens in my browser (Firefox 4.0.1), I log in, and all I see forever more is, "Norton Safe Web / Generating results... / We are scanning your feed for threats... / <<blink, blink, blink>>".  Nothing ever completes.  Any idea what's broken?

 

Thanks.

 

- John