I'm sorry Andre. The High Contrast setting for MS Windows forces the
background of SVG images to be black. I do not know how to fix this
other than turning off High Contrast.
I believe you are seeing a black sign on a black background. I believe
you color selection palettes are also all black. Can you view other SVG
images on the web? What color is the background of this image? http://www.december.com/html/demo/hellosvg.html
You should be able to view a sign with a black background and a white
line. I created an example. Please open these 2 links and tell me what
you see in each one.