Your script should be:
<?
header("Location: http://www.webpremium.com.ar/" . $dominio . "/index.html");
exit;
?>
No need for HTML here.
The error you were getting was becuase you wre already sending the body when you tried to send a header.
This is forbidden.
If you want to be able to append header information after html tags heave been declared, you need to start your scripts with
ob_start();
and end them with
ob_end_flush();
Those functions start and stop output buffering which stores all your output into an internal buffer and then sends the final output with the ob_end_flush() function, which also ends the output buffering.
