I think Gavin's response is correct --- for the situation where name of the set definition file does not begin "set".
Here is my procedure to work-around the requirement [sic :-( !] that name of a set definition file begin with "set".
My reading question (Just-In-Time) assignments are documented in files with names of the form RQ-#-#.def, e.g., assignment RQ-4-2 (to be completed after initial reading of text section 4.2 but before first class discussion of its topics) involves dates, header files, problem files listed in RQ-4-2.def. In HmwkSetsEditor/HmwkSetsEditor2, after selecting the set definition file from the pop-down list, I MUST also enter the assignment name ("RQ-4-2") in the subsequent box labeled "with set name(s):"/"Import sets with names:". After clicking on the TakeAction button, I receive a green=success message about 1 set added and a red=failure nattering saying (incorrectly) that "The setDefinition file name must begin with set".
Note: there is not a generalization of this work-around to handle importing multiple sets.
I would like to echo one of my previous requests to developers:
Please remove the archaic requirement that the name of a set definition file begin with "set".