Manfred,
Thanks for the login. When I run the template through the HTML validator at validator.w3.org I see that there are some minor validation problems. Generally, its a good idea to make sure the templates validates (or comes close) before you get too deep into browser problems. In your specific case, I don't see anything that I think would be a major issue though, although it does complain about some unclosed tags such as <br> instead of <br />.
If anything, it looks to me like the issue may be CSS styling on the label tags. Does anything change if you give those a display: block?
On Bright Side of Life, the issue may be that I have a different set of source data and HTML output than you do, so I wouldn't put too much stock into it working there.
UPDATE: After looking at the HTML a little more, its probably worth checking out the way the <dd/> and <dt/> elements are floated. There's lots of inconsistency in floats between IE and other browsers.
Thanks,
Jeff