I've got a story up on FanFiction.net and have now reached 15 chapters, it's telling me to convert documents to story/chapter format but they are! How do I add my new chapter??

Idk. Sorry

idk if this will help, but this is how i do it
go 2 the document manager thingy and do the upload a new chapter thing
then either My stories
click the story u want 2 add 2
hit content/chapters
add the chapter by selecting the document frm the doc manger
-or-
after the doc manger, hit new story
and select ur category and all that stuff,
after that i think its the same as adding on

hope that helps:)