[otrs] Problem sending attachment

I think this is a very simple question, when i try to send a mail with attach to respond a ticket the system report Software error: CGI open of tmpfile: Permission denied For help, please send mail to the webmaster (webmaster@xxxxx.gob.pe), giving this error message and the time and date of the error. I dont find any reference to this in the documentation, faq, or troubles Any advise ? Hernan