The good folks at FeedBurner have pushed some changes recently that has affected the design of the feed count badges. See some example below:
The lower half of the badge where it says "By FeedBurner" is no longer rendered as a transparent graphic and hence you see that ugly bar at the bottom.
If you are displaying this FeedBurner badge on your site, read this workaround to hide that lower portion of the graphic.
Open your blog template and enclose the badge image inside the following div code.
<code><div style="overflow:hidden; width:88px; height:19px"></div></code>
Related: Change Text of FeedBurner Badges