You do not have to install Service Pack 1 in order to install Service Pack 2 which is now available.
Service Pack 2 includes the most recent fixes, as well as all fixes included in Service Pack 1.
Important: You cannot install this update on a computer that already has Autodesk Inventor 2012 software installed. A separate Service Pack 1 is available for the Autodesk Inventor 2012 line of products.
This Service Pack 1 updates the standalone version of Autodesk® Inventor® View 2012 for all operating systems and languages.