From Flash, what options do I have for controlling an I/O board plugged
into the PCI bus on a Windows computer? The documentation for the
board states that it comes with "a set of I/O libraries and drivers
for users creating their own custom programs... and is compatible with
most Windows based languages (DLL and VXD)".

The Flash programming language (ActionScript) has no facilities for
directly calling DLLs or accessing memory, so controlling a piece of
hardware is out of the question.  I'm curious why you are wanting to
control an I/O board from Flash.  Seems like trying to reinvent the
wheel, but I might be missing something.  What are you trying to
accomplish?

Willcodeforfood,

This is for a kiosk at a museum where uses play a simple lighthouse
game that result in turning on a light at a physical map at the museum
(next to the kiosk). The map is perhaps two by four feet and is of a
body of water with lighthouses and associated lights controlled by the
computer. They want to add more excitement to the kiosk and Flash is a
great tool for doing that. It would be using Flash as a standalone
application.

I am told this I/O board--of relays that control the lights--could be
controlled from a simple server, residing locally on the computer with
the Flash standalone. The Flash standalone would communicate with the
server which would control the lights. This does not sound like a
simple solution and I was hoping for a better one. Do you agree with
this server suggestion and do you think it would be a simple one?

You appear to be the only one responding to this question. If you feel
qualified, I would be happy to take the answer from you.

Can't say I've ever done exactly what you are trying to accomplish.  I
can definitely help you with the Flash parts and if you are working in
a Windows environment I can almost certainly help you with the rest.

First of all, we need to figure out a workable architecture for your
system.  Doing so will allow us to break the problem into pieces. 
Let's make sure I understand your needs clearly before I give any
advice.

This is how I understand your situation:

You currently have (or will have) a standalone Flash application that
a user will interact with.  Upon some condition being met within the
Flash application, it will need to send a message requesting that one
specific light on your hardware be lit.  The hardware is controlled by
an I/O board that came with a set of libraries and drivers.  At some
point, the Flash application will need to reset the hardware by
turning off all of the lights to begin a new user-interaction cycle. 
The Flash application will run on the same computer that has the I/O
board.  So communication is always one way, from the Flash application
to the message-handler (whatever that is) then to the I/O board.

If any of this is even slightly incorrect or needs clarification, let
me know because even little differences may impact the best way to
design your system.

Some additional questions:

1. What operating system and version are you running on each computer?
2. What is the controller model and is there anywhere I can download the
   libraries and/or their documentation?
3. Have you installed the drivers for the I/O board?  Successfully?
4. Have you tried using the I/O board to turn on/off lights, even if only
   from some diagnostic or setup screen?  If so, what were the results?
5. Did your documentation come with any sample programs?  If so, what
   language(s) were the sample programs in?
6. What software development tools do you have at your disposal? (VB, VC++,
   and so forth)  I ask because I need to know whether you can build from
   source code or will need finished executables.  I'd prefer to just post
   the source here and let you build the software and keep the source in case
   you need to make changes later.