iPod External hard drive music folder

While upgrading to iTunes 6.0.2 I must have done something wrong. iTunes kept giving me the message "The song "xxxxx..." could not be used because the original file could not be found". I have about 10,000 songs on my external HD. I followed the directions on moving your iTunes music folder as suggested by the Apple info article. I created a new folder, selected the Keep iTunes music folder organized, consolidated, etc. However, many of my songs did not copy over the new folder. If an album had, for instance, 14 songs in its folder, only 6 or 7 songs copied over. Some of the folders that contained an artist's complete album / cd did not copy over at all. I went through my previous music folder and the new one I created and copied everything over manually (by option dragging). I hope I got all the music. Now that I hope that all my music is in one place / folder on my external HD, is there anything I can do to get iTunes on my mac mini to recognize the path to the external HD and recognize all the songs there?