"Not all required fields are filled"

First of all, nice program.

I have been able to do one way updates but in trying to sync with *equalise* selected, I get the progress bar box followed quickly with a pop-up which says "Not all required fields are filled". Job name, rules name, source, destination are all filled in. The preview function correctly identifies the changed files. When I try to run I get the nastygram. What else is there to fill in? I had the same problem on an XP machine as well as a Windows 7 machine.