Sorry it took so long to reply...I get busy and/or distracted and then it's thirty days later.
Another thing in Lectora that sometimes causes problems...if the page titles in your modules have punctuation at the end, it may fail to display some or all of the page. This is not always consistent...but I've seen it be the culprit before. I try to keep punctuation out of page titles entirely and keep titles short-ish.
And, if the title includes the word attachment or an abbreviation for it, sometimes in IE it will not display because IE believes it is trying to open an attachment in a sneaky way and blocks the page.
These might not be your problems...but they are options.