Email Using BCC

PROBLEM: Emails sent via BCC end up with the TO: field empty and some servers reject the emails if the TO: field is empty."

Hi folks, I recently moved from a certain provider who had raised their rates twice in one year (and some of you know who I'm talking about). I moved to another provider for my dedicated server, but now have a problem with email I send from my forum. I run a discussion forum and sometimes need to send notices to my members. I use an admin "control panel" in the forum software (similar to THIS forum). I send the emails out via BCC, but there is a place to put a default address, such as "members@myforum.com" . With my previous server, when I would send those out via BCC and the received emails would have the default address in the TO: field. However, since moving to the new server, the emails no longer have the default address and instead the TO: field is blank when people receive the emails. The problem is, some people
s servers require someting in the TO: field or they reject the email.

Assuming this is a server problem (mail server configuration?) does nayone have any ideas what the propblem might be? I'm using the exact same software as I used on the old server where things worked properly.