Your system or your friend's system?
What kind of error/blocking message do you get?
Maybe it's the email client that's causing the trouble? If your friend has
trouble getting the attachment, then maybe it's a security setting.
I know that Outlook Express has a setting under
Tools|Options|Security tab
to not allow attachments to be saved or opened that could potentially be a
virus.
Some email clients won't let you send large attachments (or receive large
attachments).
I like to use
http://www.savefile.com to upload large files.
I zip the files into one .zip file and upload it to that site. Then I send the
recipient an email with the URL that can be used to download the file.
