Trying to access array offset on value of type null (8)

    <div class="wrapper-body">
    <?php if($this->getVar("memberInfo")){ ?>
        <div class="row main-body">
            <div class="col7 main-body-left">
                <div class="row main-left article-detail">
                <?php if($this->getVar("articleInfo")["mStat"] == 1){ ?>
                    <div class="col0 title">
                        <h1><?php echo $this->getVar("articleInfo")["mTitle"] ?></h1>
                        <div>
                            <div class="info">
                                <a class="author" href="<?php echo $this->URL('home/'. $this->getVar("articleInfo")["author"]["mId"]) ?>.html"><?php echo $this->getVar("articleInfo")["author"]["mName"] ?></a>

tfphp\tfdumpError() in /var/www/html/web-inf/view/tfview/compile/homeDetail.html.php line 11
include_once() in /var/www/tfphp/view/tfview.inc.php line 208
tfphp\view\tfview::doLoad() in /var/www/tfphp/view/tfview.inc.php line 248
tfphp\view\tfview::load() in /var/www/tfphp/system/tfpage.inc.php line 22
tfphp\system\tfpage::load() in /var/www/tfphp/tfphp.inc.php line 219
tfphp\tfphp::start() in /var/www/tfphp/tfphp.inc.php line 223
tfphp\tfphp::run() in /var/www/html/index.php line 30
tfproject\index::run() in /var/www/html/index.php line 33