Guess what!
I've already try it and, the problem was that the record was a little bit pass the end of the file.
That's how the file was looking:

GILL01 0008-HA20000829080000020000000000000000000000000000
                                          DELR02 0250-AI20000809060053394250000000000000000000000000

I know that the technic is good, the problem is that I have a bug and I can't identify it...