First, I just want to say that I LOVE this plug-in.
I just installed an Ad through Google AdSense on my SideBar.
On Firefox: the Sidebar Ad displays perfectly on Homepage, Category pages, and individual posts.
On IE 8: the Sidebar Ad displays perfectly on Homepage, Category pages, but doesn't appear on individual posts.
I asked about it on Google AdSense Help Forum, and this guy asked if I was using WordPress and 'Add to Any' plug-in. He said he had the same problem, and it went away when he deactivated 'Add to Any' plug-in.
I deactivated 'Add to Any' and the add immediately displayed in Sidebar for individual posts on IE 8.
I'm using WordPress 2.8.5. I hope that this can get resolved, because I love the plug-in.