Hi Sacher,
Yes, that message is the best one returning a collection of MIDI fileNames (Strings) of files found in the same folder, for example:
'MIDI files/Bach Crab Canon.mid' fileNamesInSameFolderWithSameExtension
For samples, psi files, spc files, you can also use these variations:
fileNamesOnSameChannelInSameFolder
fileNamesOfSameTypeInSameFolder