Finding the? in $REQUEST_URI?page=blah

I really wouldn't ask this if I wasn't completely exausted, but the last thing I feel like doing just now is reading up on this when someone can probably answer it in a matter of seconds..... OK, I've an error handling page. Basically, I want to split (that might even be one of the functions I'll have to use) this sort of url: error.php?/pages/login.php?username=name into: /pages/login.php I'm using : header("location: error.php?page=$REQUEST_URI"); When echoing the request_uri back on the error page, it omits the error.php? bit, so I get: login.php?username=name The reason I want to do this is so that I can use a re-login form that will submit to the page the user has badly logged into, so if they logged in to main.php, the request_uri would be something like: /pages/main.php?username=name Which I'd want to rebuild on the error page, into a form, like: <form method="post" action=<? echo "$REQUEST_URI"; /* Minus the suffix the page may include */ ?>"> Username: <input type="text" name="username"><r> etc</form> Can anyone help? Thankees :) James.