Can't Add To Video Library From Two External Drives

So today is my first day with 7 and overall I love it... but I have run into a strange problem with my video library. I have many videos organized by folders on two separate (but identical, both Lacie 1TB) drives that I would like to add to my video library. I can add one drive without trouble. When I try to add folders from the second drive from within media center, the program seems to be adding it but says 0 videos found and when i check back, the folders are no longer listed under the library (essentially the same thing happens from wmp.)

It doesn't matter which drive I try - as long as I delete the libraries first and only plug one drive in, either will add its folders to the video library individually. It's when I try adding the second drive that I can't add its folders. I can always access videos through explorer and view them just fine - strictly a library problem. I can also add the folders from the 2nd new drive to any other library without problem (there are no folders in either that I included in any other libraries - it's only a problem when there are folders in the same library on the first drive.)

When I try right clicking on folders in explorer from the 2nd drive (after adding the first) and try to 'include in library,' it starts to work and then says "The folder could not be included in Videos." I've tried changing the names of the drives and the drive letters, swapping cables and USB ports and nothing works.