Problem with Internet Explorer 9

Hey Guys!

I have a big problem with my template by internet explorer 9.

Here is the link:
https://www.steinkogler.eu/offene-holztreppen-mit-wangen/

When you look this site in Chrome/Firefox in the subnavi the background-color is dark-grey, but in the internet explorer 9 it looks transparent.

Also the breadcrumb background-color should be blue and not orange.
What can i do to fix this problem?!

cheers reinki