Norton reports Trojan

When I log off Norton often wakes up and reports that it is blocking a Trojan. The IP address is 72.5.12.229 about which WHOIS says:
Location: United States [City: San Francisco, California]

NOTE: More information appears to be available at NET-72-5-12-0-1.

Internap Network Services PNAP-09-2004 (NET-72-5-0-0-1)
72.5.0.0 - 72.5.255.255
Linden Lab INAP-SFO-LINDEN-2098 (NET-72-5-12-0-1)
72.5.12.0 - 72.5.15.255

# ARIN WHOIS database, last updated 2006-10-21 19:10
# Enter ? for additional hints on searching ARIN's WHOIS database.

while Norton reports:

Details: Default Block Bla Trojan horse was detected and blocked.
All comunication with 72.5.12.229 will be blocked for 30 minutes.

Linden techies - what is happeneing?

Just a few links for you:

/111/fb/93767/1.html
http://secondlife.com/knowledgebase/article.php?id=029
http://secondlife.com/knowledgebase/article.php?id=284

Thanks