I have the same problem with sending attachments but have found that even though mail says it can not send the attachment, it has already sent it! What i do now is copy the email to myself and make the assumption that if I receive it then the person i wanted it to go to have also received it. This is not fool proof and I would like a proper solution, but it is a way round.

For big files, I simply put them on my web space and send people the link, that way they can also get files.

does anyone have an easier solution please