FCKEditor + Mediaiwki + IE6.0,7.0 Image Upload doesn't work

Hi,

I've installed the FCKEditor on Mediawiki (1.13).
When I use the image-button to upload images, I'm able to choose the one I need. I click on 'OK' and the picture is visible on my wiki-page in the background. But I can't return to this Wiki-page because the image-upload-window won't be close by 'OK' or 'Cancel'. When I click on return in the browser menu, the image upload window is closed but the picture isn't on my page.

By testing image upload with Firefox, it's working very good.

Is there a wrong browser setting in IE?

I would be very happy if someone could give me an answer.

Thanks a lot!!!