MySQLi Check New Username and query string

I would check a new user name if exist and if failed I would stay on same url rewrited page.
I have:
real url page is: mypost.php&id=1
and rewrited page is: my_post_1
so
$articleurl = my_post_1


in server behavior I set
$FailedRedirect = "$articleurl";

but I get always incorrect url as:
my_post_1&id=1

how I can remove the latest id?
Thanks

If you attach your copy of wavt_scripts_php.php then I can show you the lines to remove.

Ok attached it

You can probably just remove lines 77-83 and that will prevent it from adding the querystring back to the url when redirecting.

Thanks this work.
Then I have a similar problem with login authentication.
I would authenticate and remain on the same page.

I remove query string by add

$Authenticate->PassURLParameters = false;

and work fine

but for redirect url I get always the non rewrited url:
...
$Authenticate->RememberMe = (false);
$Authenticate->SaveLogin = (false);
$Authenticate->AutoReturn = false;
$Authenticate->PassURLParameters = false;

$SuccessRedirect ="http://localhost/mywebsite/blog/myrewritedurl_1";

$FailedRedirect = "";
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 get the url
http://localhost/mywebsite/mynotrewrited.php?idpost=1

What is your form action set to on the page? I'd probably need FTP access and a URL to reproduce the issue in order to look into it further.

Thank you very much you gave me the right indication.
I concentrated on login behavior only and completely forgot the action form.
I change the action to the: http://localhost/mywebsite/blog/myrewritedurl_1
and all work well
Thanks you and Web Assist for the great support