We just got a report that when you install Inventor 2012 on the same machine where you have previously installed 2011 or 2010, the Live Update functionality in Communication Center in the older releases 2010 and 2011 will no longer function properly.
Communication Center will always report that your product is up-to-date even if you don't have the latest service pack installed.
The bottom line is: please check the Inventor download site instead to get an accurate picture of what service packs are available.
Or even better subscribe to this RSS feed to be kept up-to-date on new updates and service packs.
Just for the record, as of today the latest service packs can be downloaded here
Note : R2012 has no service pack yet but we are working on it.