I am publishing my cpt files into HTML, white patches at bottom from end to end appeaing, please suggest the solution, screen shot attached for the reference.
Please, next time insert the image, you'll get more answers. When you attach it, we need to download the attachment, then open it in a graphics application, then delete it again.
For once I have done that process, but do not understand at all what you mean by those white patches which you indicated. What did you expect to see in that location?
Is this always happening when you publish or preview your course? I've encountered something similar when I resize the browser after publishing with HTML Scaling turned on. Normally the background is set from the Borders section of the Skin Editor. When you resize your browser after running your course, the HTML background won't recolor areas that were previously not visible because of the scaling. If this is your issue, as far as I'm aware there is no solution for this. Locking your course window to a certain size from you LMS might solve this but that defeats the purpose of scaling in the first place.