I don't think threads in Fan fiction have to be approved. I haven't posted in that board for a while, and nothing about it is stated in the rules. I am thinking that you might have posted it somewhere else. If you can remember where you tried to submit the thread and send a message to the Moderator of that section to have the extra threads removed.
And just to make sure that you get the right forum for fanfictions:
http://www.pokecommunity.com/forumdisplay.php?f=20
If you have any more questions don't hesitate to ask, this site is full of friendly helpful people.
I really need a new signature.