I was very pleased to write my first plug-in and get it working just as I wanted it to, only to find that although it worked on my testing site, when I installed it in the live site it didn't work.
If I go to the widgets page in admin, the pages gets as far as loading the heading of my widget, then stops. No other widgets show up, and the sidebar areas don't either.
But the identical code works perfectly well, as I said, on my testing site.
Any ideas what could possibly be going on?