LR 2.7 is much too old to be able to import these files.
You have use the free DNG converter to convert your files to dngs that LR can import.
The DNG converter works on the folder level - i.e. you select a folder and not individual files.
Also make sure to set Compatibility to Camera Raw 5,4 and later in Preferences.
Thanks so much for the information. Should I need to contact you at a later date for help, is there a direct way to do so without going through Adobe Communities. (I do well with Lightroom, but I am less experienced on the "computer" side.)
While the above will work I would recommend the relatively small investment (way lees than the camera) of an upgrade as Lightroom is very different now.... many new tools and a whole new processing engine...
Sorry, I don't do "support", apart from answering questions on the forums.
If you have Lightroom related questions, post them there, and you will most likely get help from someone.