表格使用HTML DOM Parser进行报废

I would like to scrape the table t-02 from https://wyniki.tge.pl/wyniki/rdn/ with HTML DOM Parser. I created simple code but I was getting errors:

Fatal error: Call to a member function find() on null in /Users/piotrek/Sites/foo/index.html on line 3

My first code:

<?php
    include ("simple_html_dom.php");
    $html=file_get_html("https://wyniki.tge.pl/pl/wyniki/rdn/");
    $tables=$html->find("table[@class=t-02]");
    foreach($tables->find("tr") as $a) {
        foreach($a->find("td") as $element) {
            echo $element;
        }
    }
?>

I changed the code to print innertext and it worked:

<?php
    include_once ("simple_html_dom.php");
    $html=file_get_html("https://wyniki.tge.pl/pl/wyniki/rdn/");
    $title=$html->find("table[@class=t-02]",0)->innertext;
    echo $title
?>

I changed only code so what was wrong with first approach? What was the reason of fatal error?

The error is saying that the $html object is null, so there is nothing to perform the find method against. Do you have the simple_html_dom.php file in the same directory?