Okay, so I have this problem. I connected my iPhone to my home computer, but after a while, everything WIPED OUT and then I restored it on this other computer. So, the other day, I wanted to put an audiobook from my home computer onto my iPhone, but it didn't work, because it said it'd erase everything. I saw I didn't have the 'manually manage' checkbox on, so I went onto the other computer, checked it off, but it still says it with the 'Warnining!' thing... how do I fix?