Cant import wav.files

I have a problem trying to import some large wave files I got on a CD from a friend. When I try importing them in the pool it says “invalid file or not supported file” or “not supported medium” etc. I think it is recorded at 24 bit/48.0 khz. Could this be the problem? Btw when I try to change my project setup to 24 bit/48.0 khz it says it cant do due to projects internal sync or something. How do I change that?
Anyway, the guy I got the CD from have used them in a multitrack program called Audacity on Win PC. It was originally protools files from Mac, but he did change them so it could be used on whenever audio track program…
So basically what can I do to allow the import of these files?
I have Cubase Essential 5 btw…

Go into Prefs and reset the Import Audio dialog box to show. Here, it will ask if you want to convert to project rate.

Well, I have changed the projects sample rate so it is the same as the wave files sample rate, but still “invalid or not supported file”. Does it happen to be different types of wave files? I though Cubase could import them…

Are you trying to inport the files direct from the CD?

No, I have saved them on my harddrive Vista OS (C:). I dont know what to do now…

Are they read only?

Not sure what you mean? I am certainly sure they are not corrupted, so I cant understand why Cubase wont allow them…But is it more than one kind of wave files?