my dear brother you should download compatibility pack for microsoft office,its free you can download it fromhttp://www.microsoft.com/en-us/downl...ails.aspx?id=3
after installing this you can easily open all new office file formats in 2003 version.

no need to install office 2007, and error is due to non compatibility of board of you computer it needs x86 types board and newer board...but you should not worry as your problem will surely be solved by installing above pack