Editing a css based template
I am having trouble editing a css based template and I am pretty sure I am doing something wrong. I recently bought a css based template from a popular website.
My trouble is that when I choose to edit the index.html page the layout is all messed up. The stylesheet is attached ok and it displays perfectly fine in the browser however, it's only when I am in edit mode that it does not display correctly. This makes editing the index.html page difficult.
I am currently using dreamweaver MX to edit the page. Is this correct behaviour or do I need additional/better software to do the job?
If so, what do you suggest?