I have a Plone server running on CentOS, I have multiple instances of Plone running 4.0 and 4.1, I also have multiple sites. I am new to linux and haveing problems getting Apache to work with multiple virtuale hosts. The first host listed works just fine but the second host does not. I get the following error message when I start HTTPD:

Starting httpd: [Mon Nov 07 14:38:31 2011] [warn] VirtualHost ordevel3.ucdavis.edu:80 overlaps with VirtualHost ordevel4.ucdavis.edu:80,
the first has precedence, perhaps you need a NameVirtualHost directive.

What am I missing to get the virtual hosts to work correctly?

Below in my syntax in httpd.conf.

 <VirtualHost ordevel3.abc.edu:80>
 ServerAlias   ordevel3.abc.edu 
 ServerAdmin   [email protected]
 ServerSignature On

    <IfModule mod_rewrite.c>
   RewriteEngine On

  # serving icons from apache 2 server
   RewriteRule ^/icons/ - [L]
   RewriteRule ^/(.*) \
      http://localhost:8080/VirtualHostBase/http/%{SERVER_NAME}:80/itsdevel3/VirtualHostRoot/$1 [L,P]

    </IfModule>

    <IfModule mod_proxy.c>
   ProxyVia On

   # prevent the webserver from beeing used as proxy
    <LocationMatch "^[^/]">
     Deny from all
    </LocationMatch>
    </IfModule>

    </VirtualHost>


    <VirtualHost ordevel4.abc.edu:80>
 ServerAlias   ordevel4.abc.edu
 ServerAdmin   [email protected]
 ServerSignature On

    <IfModule mod_rewrite.c>
   RewriteEngine On

  # serving icons from apache 2 server
   RewriteRule ^/icons/ - [L]
   RewriteRule ^/(.*) \
      http://localhost:8180/VirtualHostBase/http/%{SERVER_NAME}:80/ITS/VirtualHostRoot/$1 [L,P]

    </IfModule>

    <IfModule mod_proxy.c>
   ProxyVia On

   # prevent the webserver from beeing used as proxy
    <LocationMatch "^[^/]">
     Deny from all
    </LocationMatch>
    </IfModule>

    </VirtualHost>