@Guillermo: Very useful remark, it made me review my code. First of all, I refactored it to assure the address is written correctly, that is, with a separator '\' instead of '/'. (I suppose there is a method to convert paths from Pharo to DOS, but I couldn't find it, so I reinvented the wheel.)
Still, nothing happens.
Then, I evaluated
WinExplorer explore: 'D:\Sonoteca_sample\CRIANCAS\criancas_001.wav'
putting the argument by hand. This is a file that exists and the argument worked well when introduced directly on the Win explorer search bar, without complaints from Windows. Still nothing happens, and the Inspector tells a WinHandle(@ 16r0000001F).
Is the #explore: method the right one to use? (I mean, to open the file with the registered program in Windows).
This is quite annoying, because apart from that the app is working well in Pharo, even if it needs some cleaning. But after a lot of weeks of work (I'm a beginner, I go very slowly in my spare time) I came to the conclusion that it was useless work, because I can't communicate with Windows shell, which is a very important part of my aims.
[Side note:
What I'm building is a very simple app, ment to organize and classify my field sound recordings. A kind of database for a sound library. It has only 2 classes: SoundRecording and SoundLibrary. And a few presenters. SoundLibrary holds <recordings> (aSet), <tags> (aSet) and <directory> (aFileReference, which allows the library folder to be movable). A SoundRecording holds a bunch of properties needed for professional information and editing on sound files, plus an <address> (a relative FileReference), which is the central piece for identifying each recording/file. There is some automatic methods, including a scanner to search for files in the library and automatically create SoundRecording objects from each file found. This is crucial, because by now I have thousands of recordings.
Next step would be to do the same with my books/docs library, which also goes by thousands and is an awful amount of garbage - non organized, classified and cross referenced information is nothing more than garbage]