You're using the new document library experience in Microsoft SharePoint Online.
You're running Microsoft Office 2007.
However, when you try to open an Office file from a SharePoint Online site by selecting the option to open the file in the client application, you receive one of the following error messages:
The Webpage cannot be displayed.
Some content or files on this webpage require a program that you don't have installed.
Or, you receive a "How do you want to open this file?" dialog box, and no Office 2007 applications are included in the list.
This issue occurs because it's unsupported to open Office 2007 files in a client application directly from SharePoint Online libraries that use the new experience.
Any version of Office that's currently in mainstream support works in Office 365. These include the latest version of Office, Office 2013, and Office 2011 for Mac. Earlier versions of Office clients in extended support may work in Office 365 with reduced functionality. For more information, see System requirements for Office.