I just download Atahualpa 3.7.3 yesterday to begin a new blog and have been unable to get AdSense ads to appear in the Left Sidebar Widget using the Text widget.
I had an ad appear briefly when I first put in the HTML code this morning (ad was for Zazzle) but nothing since.
I saw that there were issues with earlier versions, but I figured that the fixes and patches would have been incorporated into 3.7.3.
URL is: grandpermonth.com
PS--I am relatively new to blogging let alone all of the HTML stuff. I am not a coder for sure.