Prompt HTTP exception after page jump (Internal server Error): An unexpected situation occurred when the server tried to execute the request

Prompt HTTP Error after page jump (Internal server error): The server encountered an unexpected condition while trying to execute the request.
index.php Jump to chkadmin.php hint (server error
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HTTP Error (Internal server error): The server encountered an unexpected condition while trying to execute the request. ）

index.php Code:

chkadmin.php Code

<?phpclass Chkinput{var $name, var $pwd, function Chkinput ($x, $y) {$this->name= $x; $this->pwd= $y;} function Checkinput () {
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