Got it to work on the iPhone & iPad...which broke it for desktop iBooks & Readium
Removed the "../" from the file paths in the TOC doc and then iPhone iBooks linked the documents properly. BUT desktop readers don't link the TOC. Take out the "Text/" and just put the file name, the desktop readers link properly, and mobile devices don't. It seems like a horrible catch-22, as well as being an incomprehensible error because other documents with the full file path read correctly on all platforms. But I can't find any other variable to try to make it work on all platforms.