Same problem here. If I try to open any of the .rat files in randytab, there is an error message that "This is not a valid RandyTab file". I can see that the copyright in the current version (1.1) is from 2000, and that the website that is indicated in the "about" window does no longer exist. I also notice that if I try to save a file from within RandyTab, the only available extension is ".rtab".
So, a question to all of you who have a working copy of randytab, could you please tell us which version you are running, perhaps also if you have an old installation file lying around (if it's some other version than 1.1)?