Originally Posted by cloudyvisions
Do you think it might be something wrong in the HTML file itself causing the major break in lines?
Yes. If you tried two methods with the same results the html would seem to be the culprit. If you open the program in Kindle4PC or other such PC reader do you see the same result? How does it look in calibre's viewer? At the point where you see the gaps what is in the html code at that point?