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.

Should work for everybody:
http://signbank.org/sp16/glyphogram.php?style=svg1&size=1.9&line=FFFFFF&back=000000&pad=10&text=M18x29S14c20n19xn29S271063xn11

Should only work with High Contrast:
http://signbank.org/sp16/glyphogram.php?style=svg1&size=1.9&line=FFFFFF&pad=10&text=M18x29S14c20n19xn29S271063xn11

Regards,
-Steve