error code: 10?

Have Norton Antivirus Version 10.1.2 on Mac 10.6.8

 

Message when computer starts: 

Norton AntiVirus Auto-Protect could not continue.  Please run LiveUpdate or reinstall Norton AntiVirus and restart. (Code: 10)

 

LiveUpdate for Nav for Macintosh Virus Defs failed

 

I tried both links on the Intelligent Updater downloads page: http://www.symantec.com/security_response/definitions/download/detail.jsp?gid=nmc

The first was incompatible with my version of Symantec software and it said I must use the NavM9 definitions updater, the second link worked (the second time I tried, not the first). 

LiveUpdate was then able to update Nav for Macintosh Virus Defs. 

Then on a later update it shows that it was unable to update Nav for Macintosh Virus Defs. 

The the message (with error code: 10) still appears.