百度了一下发现dede不支持PHP5.3、PHP5.4及以上版本了，主要原为是php5.4的版本废除了session_register函数 
可以采用如$_SESSION[$this->keepUserIDTag] = $this->userID;

这种方式处理完整代码如下
首先打开 include/userlogin.class.php这个文件，在287行到308行原内容如下：

@session_register($this->keepUserIDTag); 
$_SESSION[$this->keepUserIDTag] = $this->userID; 
@session_register($this->keepUserTypeTag); 
$_SESSION[$this->keepUserTypeTag] = $this->userType; 
@session_register($this->keepUserChannelTag); 
$_SESSION[$this->keepUserChannelTag] = $this->userChannel; 
@session_register($this->keepUserNameTag); 
$_SESSION[$this->keepUserNameTag] = $this->userName; 
@session_register($this->keepUserPurviewTag); 
$_SESSION[$this->keepUserPurviewTag] = $this->userPurview; 
@session_register($this->keepAdminStyleTag); 
$_SESSION[$this->keepAdminStyleTag] = $adminstyle; 
PutCookie(‘DedeUserID’, $this->userID, 3600 * 24, ‘/’); 
PutCookie(‘DedeLoginTime’, time(), 3600 * 24, ‘/’);

替换成

if(empty($adminstyle)) $adminstyle = ‘dedecms’; 
//@session_register($this->keepUserIDTag); 
$_SESSION[$this->keepUserIDTag] = $this->keepUserIDTag; 
$_SESSION[$this->keepUserIDTag] = $this->userID; 
//@session_register($this->keepUserTypeTag); 
$_SESSION[$this->keepUserTypeTag] = $this->keepUserTypeTag; 
$_SESSION[$this->keepUserTypeTag] = $this->userType; 
// @session_register($this->keepUserChannelTag); 
$_SESSION[$this->keepUserChannelTag] = $this->keepUserChannelTag; 
$_SESSION[$this->keepUserChannelTag] = $this->userChannel; 
//@session_register($this->keepUserNameTag); 
$_SESSION[$this->keepUserNameTag] = $this->keepUserNameTag; 
$_SESSION[$this->keepUserNameTag] = $this->userName; 
//@session_register($this->keepUserPurviewTag); 
$_SESSION[$this->keepUserPurviewTag] = $this->keepUserPurviewTag; 
$_SESSION[$this->keepUserPurviewTag] = $this->userPurview; 
// @session_register($this->keepAdminStyleTag); 
$_SESSION[$this->keepAdminStyleTag] = $this->keepAdminStyleTag; 
$_SESSION[$this->keepAdminStyleTag] = $adminstyle; 
PutCookie(‘DedeUserID’, $this->userID, 3600 * 24, ‘/’); 
PutCookie(‘DedeLoginTime’, time(), 3600 * 24, ‘/’);