This longplay was rejected because it did not meet the following requirements:
=> The required signature is missing from the video or is not properly formatted.
=> Longplays of "older" consoles need to have their resolution doubled with no smoothing.
In this case, the submitted video was 256x224, and needed to be 512x448.
Apart from those minor points to fix, the longplay is good and will be accepted.
You need to do the MeGUI / mkvmerge GUI part in the following FAQ:
Feel free to join our IRC channel
for specific help.
Hope to hear from you soon. ;-)