inserting a new picture. Only showing half the box

Hi,

I'm using FCKeditor for some of my websites without any problems. IN my new website i'm habving troubles with the inserting/edditing of a picture.

After pressing the insert/eddit image button the box is showing only half.

It works, that is not the problem, but future users are not going to understand it (using it)

I enclose a screenshot of the error.
It looks like a stylescheet is not attached.

Anyone familiar with this problem?

Thanks in advance

Frank