Using CLI (on WIN at least), some INI paths are relative to the current working directory. For example, if your error_log = "php_errors.log", then php_errors.log will be created (or appended to if already exists) in whatever directory you happen to be in at the moment if you have write access there. Instead of having random error logs all over the place because of this behavior, you may want to set error_log to a full path, perhaps to the php.exe directory.
