Paypal 2.4 module gives me an error described in the topic

[Kriter.io]

Hi Guys,
i've prestashop 1.4 and i should us paypal 2.4 but it does not work, it gives me the following php mistake:


Dettagli errore pagina Web

Agente utente: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2; .NET4.0C; BRI/2; .NET4.0E)
Timestamp: Sun, 10 Apr 2011 18:49:50 UTC


Messaggio: Previsto oggetto
Linea: 41
Carattere: 3
Codice: 0
URI: http://www.eroticgadget.it/modules/paypal/standard/redirect.php

my line 41 is:

$business = Configuration::get('PAYPAL_BUSINESS');

WHAT and HOW i should modify it???
please help me, it is very very urgent