Everything looked OK, except that the underscore ("_") is not one of the specifically listed characters that are permissible for the skin name and description strings in the .txt file (so, for example, "J5_Chunko" should be changed to "J5-Chunko" in those two strings - it's OK in the other places, but not those strings).
Thus, for example:
"graphics\Skins\AlbatrosD3\AD3_J5_Chunko.dds" "xxxxxxxx" "z Aircraft of J5_Chunko" "Fictional skin for use by J5_Chunko"
should be changed to:
"graphics\Skins\AlbatrosD3\AD3_J5_Chunko.dds" "xxxxxxxx" "z Aircraft of J5-Chunko" "Fictional skin for use by J5-Chunko"
You don't need to change it on this one (I've already fixed it for this submission), but keep it in mind for your future submissions.
Nice looking skin - looking forward to your next ones.