Marquee does not work under xhtml

[city2000]

Hello,
i tried to build the Cross browser Marquee script into my page.

But it does not work correctly while using the doctype xhtml,
look here http://www.bestguide.de/bg_marquee_test2.html .

While using the doctype html transitional it´s o.k.,
look here http://www.bestguide.de/bg_marquee_test.html

is there any newer version or any possibility to solve this problem

thanks