bool setcookie ( string name [, string value [, int expire [, string path [, string domain [, int secure]]]]] )
expire param type is integer, integer values in php are:
The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that's 32 bits signed). PHP does not support unsigned integers.
it means that maximum value of integer in PHP is 2147483647 if it's 32 bit's signed.
U can just use setcookie ('username', $username, 2147483647, '/', '$HTTP_HOST', 0);
this way must work I think