Php Cannot Generate System Identifier For General Entity Why Am I Getting A Warning In My Browser Do To A PHP Code?

Why am I getting a warning in my browser do to a PHP code? - php cannot generate system identifier for general entity

This is the warning:
"Warning: Can not modify header information - headers already sent by (output started at C: \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ xampp \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ www \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ Mamdouh_webpage \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ insert_recor ... in C: \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ xampp \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ www \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ Mamdouh_webpage \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ insert_recor in line 51 ... "

I must say that this code was generated by lower Dreamweaver CS3. Normally, when I try to insert a record into my database is added, but not the command, which will go to a site. Here's the code where I have the habit, and especially the line where it says "header (sprintf (" Location:% s ", $ insertGoTo ));}"

Any help is welcome.

$ Index.php insertGoTo = "/ Mamdouh_webpage /";
if (isset ($ _SERVER [ 'QUERY_STRING'])) (
$ InsertGoTo .= (strpos ($ ,'?'))? insertGoTo "&": "?"
$ QUERY_STRING .= $ _SERVER insertGoTo [''];
)
header (sprintf ( "Location:% s", $ insertGoTo));
)
?>