That old version is quite a while ago. I'm sure some additional css has been added since then. What I would do is first make sure it works using one of the built in skins. If that looks as it should then I would compare your skin to one of the included skins, preferably the same one you used as the starting point for customization. Look for additional css files, images and add them to your skin. Look for new css classes (probably at the bottom is new stuff) and add them to your skin. If you added any @imports to your style.css file, you need to also add them to the list in style.config
Another tip is any background images specified in your css, put them in the root folder of your skin and make sure they are single quoted like this:
This is needed for our new CSS combiner, as it has to reolve those to fully qualified urls.
Hope it helps,