Hey Ksenia

I'm curious what version you're using b/c I just posted a show
to my blog and it seems to be working.
Depending on the size of your blogs posting area you may want to either generate the show at a smaller size or use the new "Show Size" feature to resize the show after you made it and then upload that one for your blog.

Also, for blogger be sure to use the "Include Code" for it to show up...and for OSP you can also use the "Include Code" and then just check on HTML posting underneath the posting area and you're good to go.
<div><iframe style="border: medium none ; background-color:000000;" src="http://davidjay.com/slideshows/favs/iframe.html" title="Showit Web Slideshow" frameborder="0" height="350" width="500" scrolling="no"></iframe></div>