ADODB.Connection error from Ruby script on Apache server - ruby

Question

I have a Ruby script (non-Rails) that connects to a SQL Server database. When run from the command line, it runs fine. When executed via an http request, it generates an error, specifically when opening the DB connection. Something about the combination of the http/SQL methods is failing.
I'm running the script on a machine with: Windows 7 Ultimate (64-bit), Ruby 1.9.3p125, Apache 2.2.11. The database is SQL Server 10.0.4000, hosted on a separate (corporate, internal) server.
The script looks something like this:
#!/Ruby193/bin/ruby
require 'win32ole'
...
$qadb = nil
begin
$qadb = SqlServer.new('192.168.100.249', 'qauser', 'password')
$qadb.open('qadb')
rescue
logRegression("Rescued: Unable to access QADB: #{$!}")
end
The SqlServer class is based on David Mullet's code, found at http://rubyonwindows.blogspot.com/2007/03/ruby-ado-and-sqlserver.html (not copied here for brevity).
From the command line, the DB opens fine and I get an expected result from the script. When I call the script via my internal server (http://qatools/getTask.rb) I get the following error in my log file:
Rescued: Unable to access QADB: failed to create WIN32OLE object from `ADODB.Connection'
HRESULT error code:0x8007007e
The specified module could not be found.
I've considered that I might be missing a DLL. Other research led me to ntwdblib.dll -- I tried downloading a copy and placing it in various folders. I've also considered that I might be facing an Apache configuration issue and/or a security/permissions issue but I haven't found any solutions for those that seem to fit my specific problem.
Any ideas?