Q: iTunes library on external HD no longer can be selected

I moved from old macbook pro with Snow Leopard & iTunes 9 or 10 something to new(er) macbook pro with Lion and iTunes 10.7. I keep a different music library from my internal one on external HD. When I option-click on iTunes startup to choose the external library, it is there on my external, in its own iTunes folder with associated media folder, but the library, extras, genius etc. are greyed out & cannot be selected. This is a new finding as i tried to open my external library for the first time on my new system.

I notice that for the external collection of files, there is no file with suffix .itl, but there are 2 that have suffix .itdb. My external library was created with an older version of iTunes, not sure which, but within last 2 years. It was accessible from the External thru several upgrades of iTunes using my old machine. I adjusted file permissions on all the external library-oriented files to see if that helped access, it did not. How can I get new iTunes to recognize the library file ?   Thanks for any guidance or answers !