The frustrating part about this is that the images in the CF/SD card are all fine (no damage/corruption), it only happens after I download/import it to Lightroom (weather it be my MBP or iMac or even the Windows 7 laptop) ... when I download them to DPP, there is absolutely no problem ... so far, I've been able to isolate the problem only to lightroom ... my workaround for this problem is trying at least 2 different imports/downloads i.e. try directly with the CF/SD card in the external card reader or internal card reader and finally directly from the camera to the computer ... usually one of them works with corruption free images. But this is just frustrating and time consuming
Can you outline the exact steps you take to transfer the files?
From your original post it sounded like you are copying the files to the hard drive outside of LR and them importing them into LR after transfer to the computer.
This latest post sounds like you are using the LR import dialog to transfer the files to the computer.
I can understand the frustration - these kind of intermittent / random problems can be difficult to solve.
The only reliable way to track down the problem is with methodical testing
If you are seeing the problem on multiple computers (and operating systems), multiple SD/CF cards, and multiple card readers then I'm really stumped, as that would seem to have eliminated all possible common elements. Unless you've found some very obscure Lightroom bug.