Captivate 3 - What I record isn't always reflected accurately in the play back.

I have been attempting to use Adobe Captivate 3 to record short video tutorials.  Everything seems very straight forward until I play back my slides. I then find that what I thought I had recorded isn't reflected in the slides. For example, I may have selected an 'OK' button low down on the page.  In play back the mouse doesn't reach the OK button but appears to click half way down a page.  There must be something simple that I am doing wrong but I don't know what it is.  I just want to be able to set up Captivate to record and play back exactly what I'm doing on the screen. I don't want to have to go through every slide readjusting things.  I'm sure it is some simple set up error that I'm making. Can someone advise me please?