It's really hard to tell without looking at the PDF in question. Editing it with LiveCycle Designer would be appropriate if the form is an XFA form that was originally created in Designer, but not if it's an Acroform, which are normally created in Acrobat. There are a number of reasons that only the fields are printing, but without looking at the document, I can't say for sure.
As George mentioned, it is difficult to find out what's wrong without looking at the PDF. So, kindly share across the PDF form.
Also, how did you created the PDF??? On what OS and with which Acrobat version???