Oliver Sommer 
2009-08-26
To install Exchange SP2 on all EBS Servers (right it needs to be installed on all three EBS Servers, as all of them have Exchange components installed) you need to follow a procedure that is shown in the EBS Teams blog and a KB article:
http://support.microsoft.com/?kbid=973461
http://blogs.technet.com/essentialbusinessserver/archive/2009/08/25/how-to-install-exchange-2007-service-pack-2-on-windows-essential-business-server-2008.aspx