I have the same problem in 7 sites which had installed with WordPress 2.8.x version.
Parse error: syntax error, unexpected T_STRING, expecting ‘)’ in /home/XXXXXXXXXX/public_html/wp-includes/default-widgets.php on line XXXX
Yesterday, I attempted to delete the old WP files of 2 sites through FTP. And then uploaded WP 2.8.6 files to them. The 2 sites became normal. Today 2 sites display the same problem.
Do anyone can help to solve this problem and the same problem never appears again for forever?