CB 2.0 ClamAV Install can't Start Exim

Just to be sure... are you using the Spamblocker 4.x exim.conf file? If yes, you normally don't need to do *any* of the exim.conf edits mentioned in the help section for clamav.
And which exim.pl are you using?

Quick fix: remove the demime statement. It was obsolete and removed:
http://forum.directadmin.com/showthread.php?t=54196