importing into iPhoto from my canon 1D mark IV locking up

With my previous canon 7D i was able to plug in usb wire to my macbook pro 13", open iPhoto & begin importing images onto my hard drive. Recently i purchased a 1d mark IV & the import process starts as usual then slows down drastically & then freezes. The only way to abort is to unplug usb wire were i get a error message on my mac "the following file(s) could not be imported, the file is in an unrecognizable format." It then lists the files individually. When i go into my camera & hit the play button i also get an error message on my lcd saying "cannot playback image" with a huge yellow question mark & the same as i scroll to each file! So i shut down the camera & everything is back to normal & its like it never happened! I called canon where they walked me through a series of tests making sure i had all my firmware & versions updated. I havent called apple yet but with canon blaming it on them im sure apple will say its with the camera! Ive tried different CF cards as well as usb wires. Let me add that everything does import perfectly when i go around iphoto & use canon's eos utility. My next step is to buy a CF card reader & import using iPhoto. I just don understand since ive ALWAYS used this style of importing with my previous camera with no problems. Maybe there is an issue with my camera's usb contacts or circuitry internally? I guess i can also bring in my camera in fpr service since its covered? Any thoughts???

Get a CF card reader and use that. I've been shooting digital since the Canon D30 was released and cannot understand why people insist on connecting their cameras to their computers. Card readers are faster, more reliable and use less energy. Quit banging your head against the wall.

^^^^

I am no Pro photog by any stretch of the imagination. But, I did do a lot of reading (several months worth) before buying my first "real" camera a couple years ago. Pretty much everywhere and everyone suggested not attaching a camera to your computer as it was a pitb. Bought card readers same time I bought the camera and have never attempted attaching my camera to a computer.

Yes card readers are better. But the question is why this is happening. He's been able to import with his 7D so why not with the Mark IV.
Sounds like an iPhoto issue as he is able to use canon eos software. Some sort of bad communication issue.
Are you running the latest iPhoto software? Does it support your camera?