Plugin uninstallation does not work!

Uninstalling a plugin after deleting it for some unknown reason does not work. This is my code:

function sb_uninstall_plugin(){
	global $wpdb, $sb_ip_log;

	delete_option("sb_detection_of_spammers_cookies");
	delete_option("sb_detection_of_spammers_time");
	delete_option("sb_banned_message");
	$wpdb->query("DROP TABLE $sb_ip_log");
}

register_uninstall_hook(__FILE__, 'sb_uninstall_plugin');

PHP:

The value of the option uninstall_plugins in the table wp_options: a:2:{i:0;b:0;s:22:"sb/spammer-blocker.php";s:19:"sb_uninstall_plugin";}

I also tried using uninstall.php without any success.
Thank you for your help!

 

'Uninstalling after deleting does not work' - because it is already gone? I'm not sure I understand your question here. Worst case just FTP in and delete the files from the plug-in folder.

 

I do not want to uninstall any plugin. I am a plugin developer - and I want to make my plugin to be able to uninstall itself after deletion (cleaning all its data from the database). There is a function for this in WP API: http://codex.wordpress.org/Function_Reference/register_uninstall_hook

But it does not work for me and I do not know why.

 

Why don't you use an uninstall.php file in your plugin folder as it is recommended by the Codex?

 

You are right. I tried it first, but something went wrong (I did not know what and why). Now it works perfectly. Thanks for the hint.

 

Well, that's good to hear