Delete the Readiris plist file to resolve the issue.

1. In Finder on the Desktop click on the "Go" menu then "Go to Folder."
   ♦  You can also use the keyboard shortcut: Shift + Command + G
2. Type or paste: ~/Library/
3. Navigate to Application Support ►Readiris
4. Drag the Readiris_16.plist to the trash and empty the trash.
5. See if the program now works.