If you ever receive a COM error while importing from an Autodesk Inventor file, or any error in general then:
(1) Make sure you have Autodesk Inventor 2009 (or newer) installed on your computer, or Inventor View 2009 (or newer) from www.autodesk.com/inventorview -- that is the only requirement for a proper Inventor file import.
Also, if you had purchased Okino software prior to Jan 2008, and have just installed Inventor 2008 or newer, then you'll need to obtain a small update directly from Okino (support@okino.com)