May I suggest that you try from FIRST Brazil website.
I will link directly because the website is in portuguese, so you don't need to guess where it is.
Playing Field 2007 (Arena) - Autodesk Inventor 11
http://www.brfirst.org/central/download.php?file=66
Playing Field 2007 (Arena) - Autodesk Inventor (IGES)
http://www.brfirst.org/central/download.php?file=67