Note that Readiris is not designed to recognize complex forms. Readiris recognizes documents by converting pictures of text characters and numbers into actual text and numbers. Forms, on the other hand, contain many graphic elements such lines, boxes, check boxes and the like, which complicate Readiris' tasks.
Use the following rule of thumb if you try to recognize forms: if you would be able to re-create the form fairly easily from scratch inside Microsoft Word, Readiris has a good chance of processing it. If it would take an extraordinary effort to re-create it in Word, then Readiris will have the same difficulty.