解决方法：找开include/userlogin.class.php文件，查找以下内容：

@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

global $admincachefile,$adminstyle;
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, ‘/’);