TWAIN is an industry-standard, open specification that defines the way in which an image acquisition device (typically a scanner) communicates with an application program. With TWAIN, an application program can acquire images through any device that complies with its specification.
For your scanner, or other image acquisition device, to function properly, you need the TWAIN data source from its manufacturer as well as the 32-bit TWAIN DLLs. The required TWAIN DLLs are provided with Imaging.