That character is officially named "slashed O" in the character set, but it does have many meanings. Another one, I think, is "Oersted", magnetic field strength if I'm not mistaken.

You're using a Mozilla, and I think the bug only nukes IE. It came up a while back when Tom posted a bug report about how your messages were coming up blank. That's when I figured out the correlation with the slashed-O, and I guess I should have publicized it more prominently. Sorry about that.

You don't need to add "n/t" because the software now detects an empty message and appends "n/t" to the subject line automatically. The path of least effort is to just not worry about doing anything special to signal an empty message.