Logitech Squeezebox & Sonos Help

I have over 120 gigs of music stored on a Seagate drive inserted into a G5. Most of the music is ripped in lossless but some is also in compressed mp3. I have both a Logitech Squeezebox Duet and a Sonos Zone Bridge 90. All of my music plays within iTunes but a large number of music files will not play on either the Logitech or the Sonos. On the Sonos, the message I get says "Unable to play File Name file contents are corrupt." On the Logitech, the very same song may play. In other instances, for files that won't play through the Squeezebox, the message I get says "Problem: Can't open file for :///Volumes?Seagate%20internal. . . " Yet the same song will play on the Sonos. I've spent hours on the phone with Logitech and they were unable to help. I've not yet been on the phone with Sonos but it appears that there may be a problem with the music on the G5 but I'm not sure how to fix the problems. Any thoughts on what I can do to get all of my iTunes library to play on both devices short of re-ripping thousands of CDs?