1.  I set up a group of 18 people and mailed them all.   One of them "replied all" and it turned out that my message had only gone to 6 of the 18 people.  Can anyone tell me why this is?

2.  I sent the same group of folk an e-mail with 3 attachments which were files that had been mailed to be by 3 other people. I saved them onto my PC and them attached them to an e-mail fro group mailing.  All the files became corrupted and couldn't be opened by the recipients, some couldn't even open the e-mail to read the text!  The files open fine in my Sent items folder but when I tried mailing them to my husband - same PC, different account - they arrived corrupted.  So what happened there and what can I do about it?