Can you spot the bug

Found in bBlog code:

function maketimestamp($day,$month,$year,$hour,$minute)
{
// make timestamp format of YYYYMMDDHHMMSS
$string = $year.$month.$day.$hour.$minute.’00′;
$timestamp = mktime(substr($string,8,2), substr($string,10,2), substr($string,12,2), substr($string,4,2), substr($string,6,2), substr($string,0,4));
return $timestamp;
}

Where in there is the bug? Ok, let me help you. Imagine that somewhere in the bBlog code, maketimestamp function [...]