Skipping over Engage interaction if using Internet Explorer

Hi there,

I have a program with some powerpoint slides, and two engage interactions (timelines) each followed by a quiz. I published it for the web, put it on my server (so client could view it for textual errors) and everything is fine -- but ONLY if one uses the Firefox browser.

When you view it online through Internet Explorer -- it skips over each Engage timeline and goes straight to the quiz right after the timeline (twice it does that).

Any ideas? The client want this live (on their LMS) on Wednesday!  We're having them do a test on their LMS shortly, but I wanted to get a head start on issues.  Most everyone in this company uses Internet Explorer...!

Many thanks,

Marsha