Copying movie clips between computers

Many of my movie clips are mounted on my MacBook Pro c2009 running I Movie09 v 8.0.6. I tried to copy some of these to my I-Mac c2011 running I-Movie 10.1.8 via a usb stick. I can fond the clips easily on Finder in a movies directory under a sub file Movie Events. There does not seem to be a comparable route on my I-Mac. So I copied the clips from my MacBook and tried to import them into I-Movie on the I-Mac.

I got a message saying that some files could not be transferred - these are stabilisation files and two others. I was able to go into the clip files on the usb stick were there are two versions of the clips - the raw clips and a stabilised clip. When I tried to import the stabilised clips into I-Movie on the I-Mac, there was an error message saying that the files could not be recognised. Can anyone provide me with a reliable method of transferring clips between computers please. Should add that the clips are all HD format.