Cannot scan using CS5, Optional TWAIN plugin does nothing

Question

I'm trying to figure out how to scan using CS5 (Master Collection, 32-bit for 32-bit Windows Vista). I found references to an optional plugin pack for Photosop, which supposedly has a TWAIN plugin that works for 32-bit Windows Vista. So, I downloaded it. But, it seems like such a hack pack. There nothing to launch (run) for an automatic install. There's just a duplicate set of bewildering instructions for "installing" each plugin.
The instructions included in the plugin pack has a section that says "TWAIN (Mac only)" and only lists instructions for a Mac. Near the top of the document is the entire list of plugins. A footnote below the list indicates that the plugins intended only for the Mac are marked with an asterisk. The TWAIN plugin is in the list, but not marked. The online documentation confirms that the TWAIN plugin in this pack works for 32-bit Windows. But, it does not reveal how to install or use it.
Before you ask, yes, I downloaded the right version. Thinking the two version might have been switched, I also downloaded the Mac version. But, I couldn't even open it.
Anyway, I found multiple blogs instructing to add the Twain_32.8BA file to the folder "%ProgramFiles%\Adobe\Adobe Photoshop CS5\Plug-ins\Import-Export", launch Photoshop, then select File and Import. I'm not sure what was supposed to show up there, but nothing was added.
I know the scanner works, the scanner driver works, and the TWAIN driver works, since I can still use them with the much cheaper Serif software.
Any ideas?

Answer 1

I finally resolved most of the issue. Long story short, the scanner wasn't connected. What an idiot! The long story appears below if you are interested.
I still cannot scan from the scanner. But, I'm confident it's not a Photoshop or TWAIN plugin issue. The only remaining issue with an Adobe product is the very sketchy instructions (or lack thereof) and "install" procedures involved with Adobe's "hack-pack".
Thanks to all who took time to respond.
The Long Story
After posting my question, I continued double-checking everything, including the Serif software, which now could not find the scanner.
The problem originated when I borrowed the USB cable from the scanner (a Lexmark X6100 series all-in-one). When I returned the cable to an impossible to see set of connections on the rear, it fit perfectly in the phone line-out jack.
Oblivious to the cable problem, I attempted to uninstall the Lexmark driver software. This caused a nightmare of registry changes, security issues, and reboots. The driver software had been tweaked to work with Windows Vista. But, nobody thought to update the uninstaller. In the midst of the computer problems, my telephone service goes out. Go figure.
I eventually stumbled upon a resolve to the telephone issue by disconnecting the phone system from the Lexmark. At this point I begin to get a little suspicious of the Lexmark being a cause for both problems. I checked the phone cable to the Lexmark. But, it seems fine. I reconnect it on both ends. Still, it causes a telephone issue. At a loss for that problem and having a temporary resolve for now, I continue working on the driver issue.
With the Lexmark software finally removed from my computer, I begin installing a slightly updated version, praying I don't have to ever uninstall it. But, it won't install, reporting the Lexmark has to be on and connected. Rechecking the USB connection, I can feel that the USB cable is a little loose. Then, it dawns on me that it could be plugged into the phone line-out. Feeling around for another jack, I find one, plug in the USB, get a much more appropriate fit, and voila!. The new device driver installs.
I launch the Serif software. And, now it's able to find the Lexmark. I launch Photoshop, select File and Import, and there appears a new item, "Lexmark X6100 series ...". Now, if I could only get it to actually work.