There is no way you can convert a media playlist file, such as .m3u to actual audio file, which of course includes .m4p (MPEG-4 format used in iTunes) files as well.
At best, you can open the playlist in some text editor and check for the names of the songs and file paths that are listed in it.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
If you find entry that you feel is flagged as bad wrongly, please tell us in the discussion below with as much as information as possible so we can fix it.