I suspect your main language is not English anymore, and so not set to ID=1.
To illustrate, have a look in your install package (sql\information_additional.sql) and you will find the following:
INSERT INTO `information` (`information_id`, `information_group_id`, `visible`, `sort_order`, `information_title`, `information_description`, `language_id`, `parent_id`) VALUES (1, 2, '1', 1, 'HEADING_TITLE', 'What\'s New Here?', 1, 0);
The before last 1 in this code is your language ID. This should be set to your main language. So, find out what your main language ID is, and change all those (before last) 1's to your language ID. Then upload the SQL file again.
If it works, let the forum know it worked, or not.