I have the exact same problem...
In fact, I'm not even sure what the problem is!
I just moved to a new hosting cie (with cPanel) and at the same time upgraded to v1.85 (from 1.7). Now when I send emails (via php) it all seems normal, but no one gets my messages. The cron job doesn't work either (but maybe I didn,t enter it correctly).
Yesterday morning, I manually ran dailymail, and my followups were sent (and received). I also sent emails to my list, but no one got them.
This morning, I ran dailymail manually once again, but this time no one got the followups!
I created a list with just 2 emails (mine and my partner), and I tried to send a mailing, and we get the message I sent. But when I send them to my list of 450 people, the messages don't get through (even though everything seems ok when I send them).
We looked for the exim file, and didn't find it.
I don't know what to do...
Thanks for your help.
MP Charron
http://www.implosions.net