1) Yes, a little.

2) Ummm... is that a question?

It looks like it is refusing from a DNS standpoint. Changing your hostname won't change what the DNS says.

SPAM filters do all sorts of checking to make sure the email is valid. One of those checks is a reverse lookup on your IP. If that doesn't match the domain name then you can have problems.

My guess (from reading between the lines) is that you are trying to rewrite the headers in a way that the SPAM filter flags as spam. If you are going to send mail like this you will need to know a little more about how email works.

-Kurt