uxp detection 59000 - what is this?

Googmorning

 

I have recived this notificatin message from Norton Internet Security 2009 when I was in mozilla firefox windows:

- intrusion attempt blocked

- risk name: uxp detection 59000

- risk level: high

- URL aggression: unknown

 

 I did not find any information on the Internet, I upgrade norton internet security but there aren't upgrade on your site....

What type of risk is this? I have recived this notification only one time.

Please help