chi ball wrote:

Hi, when I load the "midifile-help.pd", pd windows give this errror: "error: midifile: unable to open wowo".

What does it mean?

It means [midifile] is looking for wowo.mid because it was given wowo as an argument in the help patch but there is no wowo.mid file in pd's path. You could use [midifile] to make a wowo.mid file and then reopen the help patch, see if it works...the wowo.mid file should be saved into the same folder as midifile-help.pd

(I use WinXP)

So you should have no trouble saving to the help patch folder, other OSs may not like that.

Martin