There's obviously a code problem somewhere in the forum code itself. When members send an email via email_messenger.asp it goes right through to the recipient. When people register on the board or try to do a resend of authenication, it fails (error message is generic, so don't have details), choking on the sending of the authentication email.
This is obviously not a corrupted file issue. I can edit both locally and remotely, and the files in all cases are identical, but I can't tell why the registration call to send_mail is failing.
Many of us are now stuck with using CDOSYS via our web host's servers, so this kind of a critical issue.