I want to position a layer defining the left and the right parameter, hoping that they layer uses this space. in firefox this works perfectly, but ie ignores this completely.

just have a look:
http://asp.upart.at/energie_ag/folgeseite.htm

how can i solve this problem, so that the layer with the main content (below) has the same width as the layer above (blue beside the picture).

thanx in advance

I thought you could only position a div for sure with top and left properties?
Are you trying to set the width programatically? If not, can' you just set the width property for both layers to the same width? or set both to 100%

What about two divs in 2 rows in a table?

From your css

#container2 {
background: #FFFFFF;
position: absolute;
left: 30px;
right: 184px;
top: 30px;
padding-right: 10px;
padding-bottom: 10px;
z-index: 1;
}

Notice you have both a left and a right setting at the same time. This may be confusing the browser.

danv - you can use top, left, bottom and right to position things.