Why can't I delete this cookie?

[Xelas]

From PHP, I'm having trouble getting the browser to delete a cookie. To chase down the problem, I have created a simple test page that just does this:\[code\]// Set cookie named MrPants with value foo to expire at end of sessionsetcookie("MrPants", "foo", 0);\[/code\]After loading that page, I see the cookie in my Firefox cookies menu. So far, so good.Then I follow example #2 here to delete a cookie:\[code\]// Set that cookie's expires time in the pastsetcookie("MrPants", "", time() - 3600);\[/code\]This has no effect. I have tried specifying the path, too; no change.In Firebug, I see the following in the response headers:\[code\]Set-Cookie ZDEDebuggerPresent=php,phtml,php3; path=/ MrPants=deleted; expires=Tue, 25-Aug-2009 15:27:46 GMT; path=/some/path\[/code\]What am I missing here?