There was an image in a div tag in Dreamweaver.
I replaced the image with a swff that's exactly the same size.
On the left side of the swff is a thin white vertical line that's not supposedto be there.
I tried fiddling with the swff and the div container.
Any advice is appreciated.
You probably have a piece of the stage showing--meaning your content is not covering the stage properly. Without seeing the page it's just a guessing game. If you can provide a link, that will help others to help you.