Watch out for relative file paths. When using them in any action, files lands in a folder (from that relative path) in root directory folder (where they're is expected, at least according to me). But, when you use the very same path in a migration, then files will land in a folder in
protected folder. I have just found this to my surprise.
To "fix" this, you need to add:
in front of your relative path (which makes it no longer relative, though).
Details on Yii forum.