While I see no problem with the font colours, here's what the Internet has to say about it:
http://www.456bereastreet.com/archive/200608/light_text_on_dark_background_vs_readability/
http://veerle.duoh.com/blog/comments/my_view_on_light_text_on_dark_background_vs_readability/
http://www.blogcatalog.com/discuss/entry/white-text-on-black-background-hard-to-read
http://www.webmasterworld.com/forum36/1655.htm
Conclusion: While it may seem perfectly fine, it looks like the majority of the world's population disagrees on light font over dark background being "acceptable". That means that selecting such a scheme perhaps is a poor choice, particularly when making it the only option.
SW-5120-1900-6153