ISIS™ (Image and Scanner Interface Specification) is a standard protocol for applications to obtain images from a scanner.
If your application requires the ISIS driver to perform scanning, you will need to install it.
Download and install the driver named "PaperStream IP (ISIS)" from the Download Page.
Tips!
If you are also using an application that complies with the TWAIN standard, make sure to install the TWAIN driver as well. Both drivers can be installed on the same computer without any issues.