Tech, thank you for helpful advice.

I am webmaster myself. I have checked site as far as a can and found nothing wrong.

Also, please, check if there are infected gif images (resolved as infected server generated messages): http://forum.avast.com/index.php?topic=45658.0
It seems that this is not the case: as I can see on my computer (no avast) all images are visible and there are no error messages.

I have checked my page on hidden iframes and didn’t found them.