Now for me as of Today: The Save Template button is working, but the expand template check box is not working, it links me to a 404 page. I just wanted to let you all know its not you or your computers, its blogger.
Here is the forum discussion on it today: http://www.google.com/support/forum/p/blogger/thread?tid=331402eb33ca277c&hl=en&fid=331402eb33ca277c00049d0cb9127627
This is an update from the blogger Known Issues Blog. They have finally addressed the issue. No ETA on a fix yet. http://knownissues.blogspot.com/2011/02/some-users-have-reported-issues-with.html
Some users have reported issues with our expanding widgets in HTML Editor and previewing in Template Designer. We are investigating and will report back once we have more information.