OpenX doesen’t display flash banners as it should

I have problem with flash banners served from OpenX. I have tried with WP plugins and with jus pasting OpenX code into the widgets, and nothing seems to work for flash banners.

It works perfectly with text/image banners but for flash the position and usualy the size is wrong. it displays a bit off widget, for 160×600 for example, banners is shrunken + displayed as square with white background around …

example picture:
https://www.amfibius.net/pix/bannerx.jpg