SOLUTION (Try this)
Hi. Yesterday I´ve bought an EPSON Stylus TX220 (multifunction: print/scan/copy). It prints very well but when I wanted to scan, I only could do it from Control Panel / Scanners & Cameras / double click in the Epson Scanner Icon. It loaded the Scanning Wizzard. I did could scan, but I couldn´t do it from the EPSON Scan desktop icon neither the EPSON Scan icon at the Epson group from Start / All Programs because the following error message was shown (approximately):
 
"Needed files not found. Please re-install the software".
(in Spanish: "No se encuentran los archivos necesarios. Por favor, reinstale el software").
 
I´ve found at the windows folders a log file called "scantwain.txt" where refers the ABBYY FineReader 9.0 Sprint program and shows the following error message:
 
====== MESSAGE ======
 Message Title: ABBYY FineReader 9.0 Sprint
 Message Text : Ningún módulo TWAIN: 
C:\WINDOWS\Twain_32.dll
=====================
 
 Message Answer : IDOK
=====================
 
TWAIN: Twain_32.dll NOT loaded!!!
 LOGGING stopped at: 06-10-2010, 01:22:48
----------------------------------------------Logging completed successfully!
 
It means the Epson Scan program can´t load the twain_32.dll file from the C:\Windows folder (because the twain_32.dll file isn´t in that folder).
 
I´ve searched the "twain" files with "Search" Windows utility and when they were found, I COPIED the "twain_32.dll" from the C:\Windows\$NtServicePackUninstall$ folder to the C:\Windows folder (in my particular case).
Then I went to Start / All Programs / EPSON / Epson Scan / clicked the Epson Scan icon and the EPSON Scan Utility was loaded successfully, and I DID could scan without problem. It worked fine too from the EPSON Scan desktop icon.
                
 Pablo, from Buenos Aires, Argentina
                
 October 2010