Corrupted cookie (solution)

I've been running a site for about a year, and recently a module (suhosin) for php was installed which corrupted the cookies of our users. After logging in, people would see blank pages and the following would appear in the PHP error log:

PHP Fatal error: Duplicate entry 'eL-MsFexnfSxZ0kZHSD70bUe7drBM37w' for key 1\nquery: INSERT INTO sessions (sid, uid, hostname, timestamp) VALUES ('eL-MsFexnfSxZ0kZHSD70bUe7drBM37wnDufHNLUFtNAiDNFzp_B8YJdRkv22Stc', 0, '38.100.123.123', 1175360047) in /home/mysite/public_html/includes/database.mysql.inc on line 66

While emptying cookies fixed the problem, I wasn't prepared to ask every single one of our users to empty their cookies. The better solution to the problem, as I learned from more experienced drupallers, was to:

If you have access to your php.ini, you can change the cookie name from the
default PHPSESSID to something else.

Before: session.name = PHPSESSID

After: session.name = DRUPALSESSID

This will cause all your users to be issued new cookies, that should be working,
and the old cookie will be ignored.

If you do not have access to php.ini, you can do this in .htaccess
php_value session.name 'DRUPALSESSID'

Or in settings.php:
ini_set('session.name', 'DRUPALSESSID');

This depends on whether your host allows the setting of this variable or not, but
it is sure worth a try.

In addition, I also emptied the access table.

Problem solved! Thanks for your help!