Music Maker MX - I don't have access to my entire soundpool. Most items keep coming up with a 'cannot find file' error. Please Help.

I don't have access to my entire soundpool. When I click to drag sounds into the recording I keep getting a 'cannot find file' error on my computer. Some sounds are working correctly, but most arent. Please let me know what I can do to fix this.

I am using Windows 7 if that helps.