If they're seeing boxes, that sounds like a fonts question. Could you post something non-sensitive here for the gurus to look at?

Management question: if you're designing the handbook and other people then want to edit, how are you managing document ownership and versioning? what's the process for getting edits back to you, or is someone else taking over? Send them a .pdf, collect their comments, send them an update … one reliable approved source for the document.