Validation Logic

I have a form. The user types in the info, hits submit, then it submits to
itself. It says $error=0, then if ($_POST['submit'], then run through all
my error checking. Each time an error occurs, $error++. So, then I say if
($error==0) then header("Location: nextpage.php"). The problem is, whenever
I fill it out with no errors, I end up with this error:

Warning: Cannot add header information - headers already sent by (output
started at /home/httpd/vhosts/fairmount.nu/httpdocs/test/top.html:12) in
/home/httpd/vhosts/fairmount.nu/httpdocs/test/sinup.php on line 104

Line 12 is just this:

if ($_POST['submit'])



Line 104 is this:

header("Location: nextpage.php");

Any ideas?

--
TresWBL
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