We've had many text widgets in our left and right sidebars with no problem. We are running Atahualpa 3.2 and Wordpress 2.7.1. Just today, my partner tried to change a text widget in the right sidebar, but the save didn't work. It reverted to the old HTML code. I came in and tried to fix it, and now NO text widget can be added. In fact, I can't add one to the left sidebar either, and I also can't add a new PHP code widget anywhere. All she wants to do is put this in a text widget:

<center>
<a href="http://www.larchmontgazette.com/testads/20090909bankad.pdf"><img src="http://www.larchmontgazette.com/testads/20090624bank.jpg"></a></center>

Previously, the links just led to a different PDF and a different .jpg file. What on earth is going on?

http://www.larchmontgazette.com, right sidebar. There should be a bank ad before the real estate ad.

OK, I found a fix for this, but I still don't know why it happened.
http://wordpress.org/support/topic/281151

I added "else" on line 85, and that did the trick. But why was it working fine before, and then stopped working? Why did this break the widget saving mechanism?