Can"t open .docx .doc with Pages '09

Everything is updated as far as snowleopard goes and as far as iWork goes. I can open .doc no problem but when the file reads .docx.doc it will not open it. I get an error message that says "Import error; The file format is invalid"

Does anyone have any idea if there is an update that will fix this issue? I know that this format of file is created by office 2007. When i had my PC there was a download to convert the 2007 format to the 2003 format. Is there anything comparable for this issue?