I am also interested in the version of the TWAIN 2.0 DSM that was in the system32 folder of the machine that was not working. The c:windowssystem32twaindsm.dl file
The most recent version 2.0.9 of this file should work fine if a second copy of the old DSM is located in the system folder.
http://sourceforge.net/projects/twain-dsm/
Jim Watters