You could try the following :
For :"Got message "An error occurred communicating with the scanning device"http://www.out-of-warranty.com/error-communicating-with-scanning-device/
For the Second Problem :
did the failed installation add any files onto
your system? if so i would delete them and copy the Scanjet 3970
onto your system from the disc, and run
the install or setup from your system.
Or you could Browse the Scanjet 3970 Setup/Install CD For the.exe & lunch it