Probably cos they aren't meeting the requirements for a story on this site. We have had a lot of users staring copious amounts of stories, like they think they can churn out novels like Dickens.
Have a look at the guidelines and story help mate. Then I'm sure your story will get approved. Nothing against you, but its the amount of users in the past who have 'promised' to continue stories then forget about them so their story inevitably ends up forgotten about.