Change design of userlists and searchable fields

hej folks,
i have to change the style of userlists.
you can take a look at a demo-version of this site on: website-schmiede.at

first i did was to show up all users side by side in one row.
this works fine in firefox, ie8 etc. but in ie6 and ie7 this wont work.

now i have a second big problem with the "search users" button in the upper right side of the userlist (it's called "Suchen und finden" on the site mentioned above).

if you use firefox and click on this "Suchen und finden" link, it fades to the middle and opens normally. but in internet explorer the fields wont be shown, as you can see on the images below.

do you know any possible solution for this problems? would be great.

thanks

firefox:


ie: