This is a security option by default to protect you from getting viruses from attachments. Just follow the steps below to disable it.
Go to Tools / Options / Security / Virus Protection
Clear the check box for, Do not allow attachments to be save or opened that could potentially be a virus.

2. Why do I get disconected every time I send an e-mail?

This is just a simple option on outlook express that will disconect the conection after sending or recieving any email. To fix this problem, just folow the steps below. Go to Tools / Options / Connection / Dial-up Clear the check box for, Hang up after sending and receiving.

3. What does the error codes mean?

691- Bad user name and password

680- No dial tone

692-Hardware failure in port or attached device

718- This error indicates a connection was made with the server and a PPP conversation started, but was terminated because the remote server did not respond within an appropriate time.This can usually be resolved by restarting your computer and attempting to connect again.