Localhost displays differently to IE/CHR error mssg online

Hello
I have two problems:
Warning: Cannot modify header information - headers already sent by (output started at /home4/laurasoa/public_html/catalog/language/english/english.php:1) in /home4/laurasoa/public_html/system/library/currency.php on line 45

This displays in IE and Chrome but not in Firefox

The same site is scrambled - almost as if it's ignoring half the CSS in IE.

Exactly the same files (I just downloaded them back onto my hard drive) work perfectly through Wamp localhost on all 3 browsers.

The site is www.laurasoapshoppe.com.au (their choice of design)

Apologies - I'm using Opencart 1.5.2.1 and line 45 is:

public function set($currency) {
$this->code = $currency;
if (!isset($this->session->data['currency']) || ($this->session->data['currency'] != $currency)) {
$this->session->data['currency'] = $currency;
}
if (!isset($this->request->cookie['currency']) || ($this->request->cookie['currency'] != $currency)) {
setcookie('currency', $currency, time() + 60 * 60 * 24 * 30, '/', $this->request->server['HTTP_HOST']);
}
}

I hope nobody just spent a lot of time trying to help me as I resolved the error message by going back to basics and reloading everything, step by step, from the original files. IE still won't go past the Guest Checkin to slide down the form for their address etc, though FF and Chrome will. Too hard.