iPhoto Backup

I'm trying to backup photos/videos from my external hard drive from my old Mac to my new Mac and it is showing "preparing to import" message in iPhoto for hours - how long should it take? Since I have a significant amount of video/photos will it cause problems?

How many photos and videos do you have that need to be copied? What's the total amount of data? Keep in mind that direct copy from one external hard drive to another is a slow process and depending on how much you have to copy, can take a considerable amount of time to accomplish.