When the NDR's are sent it is leaving the from as <> .  I tried going into SMTP Server Configuration > Advanced and changing Sender's Email from Postmaster to an email address but it still leaves the address blank.  Is there something I am doing wrong?

Thanks

Which FROM are you referring to? Is that the envelope FROM or the header FROM? Check http://www.xeams.com/difference-envelope-header.htm for differences.

Note the the envelope FROM in an NDR is always blank. This is true for every email server (including Xeams) and is done by design to prevent a message loop.