At this point I am at a loss. There are no syntax errors in the code. When I run the code on my computer, using either USA regional formats or Poland regional formats, the code returns records. (maybe it is the way I set up the mdb) It is strange that you have records returned using Spain regional formats and no records using Poland regional formats.
Have you tried your database on a different computer?
Maybe someone else will have an answer. Sorry I couldn't help