N3WWE - I have opened your BASE.RDT file using D578UV.exe dated 10 Jan 2022 (in details tab of properties on the EXE file). Then wrote a DCF file. I then opened that DCF file without error on Contact Manager 2.,70.
Any D578UV.exe dated prior to Jan 2022 will not work. See link in tom's post at the top of this thread for the updated 578 CPS. Unfortunately, it reads "1.15" in the "About" pop-up inside the program, so it looks like the old one. Look at the EXE file that was installed to see the difference.
Greg
K0MGL
