imovie will not import my .mpg movie files from my sony digicam

[Sossity]

I have just recently got my macbook pro, & one of the things I wanted to do with it is make movies, so I copied from my external hard drive to the mac hard drive the .mpg movie files my sony still/point & shoot digicam takes. I then open up imovie & go to file import, & find the folder with my movie files on the macs hard drive & they are grayed out, imovie cannot import them.