Problem with Norton Internet Security 2011 Upgrade

Currently have Norton Internet Security 2011.  Received a notification that an update was available.  Downloaded it and then got a message telling me I do not have enough licenses?  My installed version now says it is a TRIAL version that will last 15 days?  Why would the update change my version to a trial version?  I should not need to renew until June 8, 2012!