I've encountered an interesting problem of sending emails with an attachement from Max MSP. Although there are various forum threads* on the subject using the mxj net.mail.send object, I had no luck making it work with it.
But, I came up with an extremely simple solution that doesn't require any java and programming magic. If you have a mac computer then you have the Automator application.
You can than make a simple automator workflow/application that sends an email with an attachement (see the attached picture). It doesn't matter what the attachement is, it can be a picture that you export from jit.matrix or a sound file. The automator will attach it to the email and send the email to a specified address.
Now all you need to do is to run the application from max msp once you've exported an image or the sound file. You can do that by simply sending a message to max like so:
; max launchbrowser "file:///sendEmail.app"
Max msp will run your app and the email will be sent.
Hope it helps solve your problem