Reply to all doesn't reply to all

[Memo Gonzalez]

Hi, has anyone had this problem..

Someone sends and e-mail to a few people,
when one of the contacts replies to all
the message .. the person that originally
sent the e-mail receives an e-mail but it
doesn't show the other contacts..
and the other people that where copied receive
also the e-mail but without the original mailer...

does anyone know what is wrong...?

thanks