More than two weeks have passed and I was finally able to find a solution to the issue above, but first things first:

I also tried using the 32-bit version of mod_cluster (downloaded mod_cluster-1.2.0.Final-windows-x86-ssl.zip from http://www.jboss.org/mod_cluster/downloads/1-2-0-Final), thinking that perhaps this issue was caused by an incompatibility with my current setup on a 64-bit Windows system. However, I got the same Syntax error message when I uncommented the following line from the httpd.conf file that was included in mod_cluster-1.2.0.Final-windows-x86-ssl.zip:

LoadModule ssl_module modules/mod_ssl.so

Given the solution I will be describing below, the only conclusion I can reach is that there is something wrong with the mod_ssl.so module supplied in both mod_cluster windows binary packages.

Perhaps the mod_ssl.so was not correctly compiled or is not the correct file for a Windows distribution. Too bad that, judging by the overwhelming feedback to my original post, nobody seems to care about it. I'm hoping that the solution below will help somebody in the future.

SOLUTION:

1.  Downloaded httpd-2.2.22-win32-x86-openssl-0.9.8t.msi from http://apache.mirror.rafal.ca/httpd/binaries/win32/.

2.  Double-clicked on the file and entered the following information when prompted:

Network Domain

Server Name

Server Admin

3.  Chose to install:

for All Users, on Port 80, as a Service (Recommended)

4.  Setup Type: Custom

5.  Build Headers and Libraries

- chose ‘This feature will be installed on local hard drive.’

- left everything else the same

6.  Default path: C:\Program Files (x86)\Apache Software Foundation\Apache2.2

7.  I started the Apache HTTP Server as a service and it started up fine.

8.  I stopped the service, uncommented LoadModule ssl_module modules/mod_ssl.so in C:\Program Files (x86)\Apache Software Foundation\Apache2.2\conf\httpd.conf and ran httpd.exe from the Command Prompt with the -t flag. There were no errors. I started the Apache HTTP Server service and it ran fine.

9.  To be able to use mod_cluster, I copied the following files from mod_cluster-1.2.0.Final-windows-x86-ssl.zip\httpd-2.2\modules to C:\Program Files (x86)\Apache Software Foundation\Apache2.2\modules:

mod_proxy_cluster.so

mod_manager.so

mod_slotmem.so

mod_advertise.so

10.  I also copied the following section from my previous httpd.conf file to the new C:\Program Files (x86)\Apache Software Foundation\Apache2.2\conf\httpd.conf file:

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule proxy_http_module modules/mod_proxy_http.so

LoadModule proxy_cluster_module modules/mod_proxy_cluster.so

LoadModule manager_module modules/mod_manager.so
LoadModule slotmem_module modules/mod_slotmem.so
LoadModule advertise_module modules/mod_advertise.so

# MOD_CLUSTER_ADDS
# Adjust to you hostname and subnet.
<IfModule manager_module>
  Listen IP_ADDRESS:6666
  ManagerBalancerName mycluster
  <VirtualHost IP_ADDRESS:6666
    <Location />
     Order deny,allow
     Deny from all
     Allow from IP_ADDRESS
    </Location>

    KeepAliveTimeout 300
    MaxKeepAliveRequests 0
    #ServerAdvertise on http://IP_ADDRESS:6666
    AdvertiseFrequency 5
    #AdvertiseSecurityKey secret
    #AdvertiseGroup IP_ADDRESS:23364
    EnableMCPMReceive

    <Location /mod_cluster_manager>
       SetHandler mod_cluster-manager
       Order deny,allow
       Deny from all
       Allow from IP_ADDRESS
    </Location>

  </VirtualHost>
</IfModule>

11. To answer my question regarding OpenSSL in my original post:

Yes, I ended up using OpenSSL to generate a self-signed certificate, but since OpenSSL came bundled with the Apache HTTP Server, I did not need to download or install any additional files. The PDF document available at the following link was a great resource on how to install and configure Apache 2.2 with SSL on Windows:

http://blogs.technet.com/b/port25/archive/2008/01/04/technical-analysis-installing-apache-with-ssl-on-windows.aspx