Help - Clip Zip wont read SD CARD. Rockbox wont either

I think your problem is that Rockbox needs to initialize the database and construct it. In Rockbox, highlight database and give it a long press. Click on initialize now. If your card has many songs on it, I suggest having patience while Rockbox builds the database. Or you could play music using the folders menu, however playing music will make Rockbox take much longer to build the database.