HI WEBPC,
Thank you for posting the screen shots. They reaffirm that your driver installation was successful. So, I thought, either I'm missing something (that never happens :-> ), or possibly this is an issue where one motherboard/chipset combo works, and another
doesn't. That lead me to try installing the Xerox driver another way. I was successful this time, but only partially. Here's what I did:
Install the driver via the DM510_4.6.10.1101.EN.msi package. For me, as before, the install completes 100%, but Device Manager is not happy:


Now, the PC has the Xerox/Visioneer driver files installed, even if they are not working properly. So time to try it the old fashioned way:

Browse for it:




Click Yes:

XP and forward use the TWAIN driver :



Whoppe! Now I've got it!

Read on . . .
I test it, but immediately lose my newfound joy :-(

More red ink:

Try a diagnostic:

This just doesn't make any sense:

Maybe that test thinks it's working, but the scanner lamp hasn't lit up or moved an inch yet.
So try MSpaint.exe's scanning facility :

I get the driver's dialog form, I'm starting to feel some joy again :

but MSPaint filed to acquire the image :

Now I'm really miffed! I finally get the driver to install in Win8.1, and the scanner still doesn't work. (Oh, btw, I am certain that the scanner works because there is a Win7 VM on this machine (via VMware
Workstation), and the scanner works fine as frog hair in that VM.)
So like I said, "I was successful this time, but only partially". And we all know that being close only counts in horseshoes and handgrenades.
Time to drop back and punt . . .
Maybe the driver I downloaded is corrupted. After all, I did have to install it manually to get it to install at all. I uninstall the driver again via Programs and Features :

Go back and download the driver again:

OMG, did I download the wrong driver?
D'oh!
I have the "000" scanner and I've been trying to force feed the PC with the "100". No wonder it's not working.
D'oh! to me again!
Short end of the story: The "DM510_4.5.10.0122.EN.msi" driver (specifically for the "000" scanner) installed without issue and the scanner works as advertised in both "Windows Fax and Scan" and MSPaint.exe .
Even though a little embarrassing, I decided to post the entire resolution to my particular problem here to benefit the community. I suspect that the other posters who can't get their Xerox DocuMate 510 scanner up and running in Windows 8.x may also be downloading
the wrong driver. Btw, that part number can be found on the bottom of the scanner.
I'm glad it's working now. I really like this scanner.
Thanks again for your screen shots and helpful comments.
Regards . . .
P.S. I haven't installed the currently available One Touch version OT4.6.2014.9305.EN, so I can't attest to it's proper operation. I heard you mention your problem with it. If it helps you, I have the earlier version that was posted as of September 2014.
It's version OT4.6.1913.12093.EN.msi. PM me if you'd like to test that version.