hi there
i had the same problem, too. importing references from all journals faced this problem. but, i solved it so easily.
at the fiirst, let see was the cause of this error. i saved my library file in the same folder of the software in the windows drive directory, therefore, any changes couldn’t be saved. new references or styles could be countered as the new changes for the ENDNOTE program that couldn’t be saved in the library.
i couldn’t find any solution for this annoying error. but i find the solution in changing of the library directory. in other words, i saved a copy of the library file in another drive than “c:” and this is it. this is the solution. the “choose import flter” error didn’t appear again.
i wish you can solve this problem, too.