How to remove url querystring after login

After a person logs in, it is passing the original parameters to the next page from the querystring. Is there a way to drop those? On my Webassist > MySQLI > User Authentication, there isn't a checkbox for pass querystring parameters or don't pass querystring paramets. Attached is a screenshot. Here is my code:

<?php
if ("" == "") {
$Authenticate = new WA_MySQLi_Auth($sdpc_i);
$Authenticate->Action = "authenticate";
$Authenticate->Name = "sdpc_login";
$Authenticate->Table = "users";
$Authenticate->addFilter("username","=","s","".((isset($_GET["username"]))?$_GET["username"]:"") ."");
$Authenticate->addFilter("password", "=", "s", "".(isset($_GET['password'])?sha1($_GET['password']):"") ."");
$Authenticate->storeResult("userID","userID");
$Authenticate->storeResult("username","username");
$Authenticate->AutoReturn = false;
$SuccessRedirect = "read2.php?page=1&verify=T";
$FailedRedirect = "error.php";
if (function_exists("rel2abs")) $SuccessRedirect = $SuccessRedirect?rel2abs($SuccessRedirect,dirname(__FILE__)):"";
if (function_exists("rel2abs")) $FailedRedirect = $FailedRedirect?rel2abs($FailedRedirect,dirname(__FILE__)):"";
$Authenticate->SuccessRedirect = $SuccessRedirect;
$Authenticate->FailRedirect = $FailedRedirect;
$Authenticate->execute();
}
?>

I'll have to add that setting back. For now you can edit the authentication.php file and remove this line:

$this->Redirect = $this->addQuerystring($url);

That will prevent it from adding the url parameters.

I don't appear to have that line in my file. Attached is my file.

That is an older version of that file... I've attached a newer one. In this one you can just change the setting on the top of the page on line 49, just update this line:
$this->PassURLParameters = true;

to:
$this->PassURLParameters = false;

Thank you so much!

When I used the new file that you sent, now all my login forms don't work. I just get a blank white screen. Is there a way to update my existing file?

Can I get FTP access and a URL to debug? I'll take a look and get it fixed. I'd need that to update your old file as well, but I think the best option will be to get the new one working for you.