Lacie external hard drive issue

I use my LaCie external hard drive to back up my macbook via time machine. Recently I had to erase my macbook hard drive due to corrupt software files. When I restored the hard drive using my LaCie back up, thousands of my iPhoto pictures were not restored (the files names were there, but no pictures were displayed just a big image of an exclamation point). I tried to enter my LaCie hard drive to verify the date of the latest back up but the LaCie hard drive stated that I do not have permissions to view the files.

My question is how do I gain/manage permissions to view time machine files on my LaCie hard drive?