BleepingComputer.com: Media Centre not picking up files?

I have a RetailPlus HDMI Media Player that I use to view movies and TV shows downloaded onto my laptop. Originally, I had a 500 GB external hard drive that I kept all my files on and connected that to the HDMI player. Worked like a dream.

Recently, though, I removed a 1 TB hard drive from my old desktop and put it into an enclosure that I purchased. I already had a lot of files on that. But when I hooked that drive up to my HDMI media player, although it shows the root directories (for example, The Simpsons Season 1, Season 2, etc), when I select a season, the episode files within the season folder aren't showing up.

I connected my external HD to my laptop just to make sure the files are actually there, and they are...they play perfectly well on my laptop. They just aren't showing up at all through the HDMI media player. I'm completely stumped and have no idea what to do.

Any advice would be greatly appreciated! Thanks in advance.