On the top right if you click "Member Sign In", the Simplemodal Login pops down beautifully.
The problem is in the ERROR messages: the empty_all, empty_username and empty_password errors display nicely, but when there is an invalid username and password combination, the #login_error div displays, but it is empty.
(the orange box should have an error message in it)
I tried deactivating the plugin and logging in at wp-login.php, and then it wouldn't display those particular login codes. After re-activating the Simplemodal Login, now no error messages display on the wp-login.php page (though the empty_x messages still display correctly in Simplemodal).
I've tried changing the theme back to default, uninstalling the plugin, and then installing the default version, etc. Zero luck.