"I am having problems attaching zip files to a forum. "
Are you trying to send direct to a forum on the web? Many Forums do not allow uploading of compressed files, as they can easily contain virus's. That could be why the recipient is only receiving the original links
It doesn't seem to be the root of the problem, but, as Saltgrass says, some mail/ISP providers, do have an automatic warning when you try and send a compressed file. This is my Live Mail warning, for example.
Note: To protect against computer viruses, e-mail programs may prevent sending or receiving certain types of file attachments. Check your e-mail security settings to determine how attachments are handled.
Have a look in the attachment section of the forum to which you are trying to send, and see if they do include compressed (zip:rar:etc) files.