I tried adding this, but still getting 404 errors on 301 redirects. Did I put it in the wrong place? This seems to relate to 302s, rather than 301s.
function wp_redirect($location, $status = 302) {
global $is_IIS;
$location = apply_filters('wp_redirect', $location, $status);
$status = apply_filters('wp_redirect_status', $status, $location);
if ( !$location ) // allows the wp_redirect filter to cancel a redirect
return false;
$location = wp_sanitize_redirect($location);
if ( !$is_IIS && php_sapi_name() != 'cgi-fcgi' )
status_header($status); // This causes problems on IIS and some FastCGI setups
header("Location: $location", true, $status);
global $wp_query;
$wp_query->is_404 = false;
}
endif;