I've had quite a few problems to get the Acer ScanPrisa 640P to work with WindowsXP. Unfortunately the only sites dealing with this problem where russian, and I don't speak any russian at all. Thanks to the help of a friend in irc (/me waves to Daan) I finally managed to make the whole thing work.
So for future reference, and to help other non-russian speaking people with the same problem, here's how I did it:
Note: This worked for me. I can not guarantee that it will work for you as well, but it's definitely worth a try
I've found some extra info about the problem on a different russian site:
http://www.computery.ru/upgrade/faq/...g_098.htm#Acer
ok now for what you have to do...
(Make sure your Parallel Port is set to EPP in your BIOS)
1. COMPLETELY uninstall the MiraScan dirver:
First go to "add/remove Software" under windows and remove it from there.
Then go to your 'windows\twain_32' directory and remove the mirascan folder in it (or what is left over from it).
Now open regedit and clean your registry from all 'mirascan' entries, especially the ones in the twain section.
2. When you've done that, copy all the files in your '..mirascanv3424p\TWAIN' folder to the two following folders:
first to 'windows\system32\dllcache' (otherwise windows will restore the dlls when you overwrite the ones in the windows dir)
then also copy them to your 'windows' dir
(always overwrite the existing files!)
Now a windows-dialog will propably pop up and ask you if you really want to do this...blahblahblah. Just ignore it. YOU HAVE TO KEEP THE NEW DLLS IN THE WINDOWS FOLDER!
3. reboot your system
4. now start the mirascan-setup. choose CUSTOM INSTALL and only install the first two things (can't remember what exactly they were called), but do _NOT_ install the EPPMINIDRIVER thing!
If you now try to "acquire" the twain source with a program, you should get a "scanner not found" error. At least that is what I got at this point.
5. go to the windows device manager and remove the 'color flatbedscanner' if it's there. If it's not there, this should be ok too. It was there when I did it.
6. do the same thing you've done under point 2 AGAIN. In other words, overwrite the dlls in the windows folder with the ones in your mirascan\twain dir again. (no idea if this is really necessary, but it have done it.)
then reboot your system.
8. start the mirascan-setup again. choose CUSTOM INSTALL, but this time only install the last thing called EPPMINIDRIVER or something. untick the other two things which you should have already installed under step 4.
when the installation is done, use the windows wizard to add the EPPSCANNER 'color flatbedscanner' and reboot your system for the last time.
Congratulations, your scanner should work now. Don't blame me if it doesn't, but write a hate mail to ACER aka BENQ instead :P
