The Add This "share" button is not showing up, just the "alt" text, and when I try to select to display individual service buttons instead, the set of default buttons is very odd (Delicious, but no Facebook???) and some of *those* images are showing up as broken. If I try to specify the desired networks as a custom set, it doesn't show up at all.
I pulled up the src URLs for the missing images, supposedly cached images from your servers, and I'm getting 404 errors. I'm running the current version of the plugin and WP 3.5.
This looks like a problem on your end. Please fix. If it's still broken by the time I get home, I'll have to bail on your service and go with something that works.