I have the same error. I disabled my localization (WP_LANG on wp-config.php) and the error is gone for the time being.
I finally got it working. Just clicking “reset importer” didn’t work. I had to go to the wp_options table and remove the row with “import-blogger”. Which is funny, since this is, basically, all the “reset importer” does, according to the restart() function on import/blogger.php.
