I have had that problem in the past as well, but I am not completely sure of the solution >> the RSRC file is in the PM program file and the program, while opening, is looking for it. When the message comes up, I think it also includes a question as to the location of the RSRC file; once browsed and located, the program opens and the problem should end.
What might be helpful is to do a "search" first to locate the RSRC file and to mark down its location. Then, when you open PM again, you will be able to browse to find its location.