"Page Creation Throttle 2" is a measure put in place to prevent spam pages as some users in the past have uploaded dozens upon dozens of spam pages in rapid succession that required hours of clean-up to delete their spam. Each attempt to post your story likely resulted in the blacklisted filter marking your IP as having added one page (even if that page wasn't created due to the filter) and triggered the warning.

The easiest solution would be waiting until tomorrow and uploading your story then (making sure that you don't trigger the filter multiple times again).

I think this happens when one tries to upload a blacklisted content page multiple times. For reference, an Edit Throttle is when a filter word is set off. Try resetting your browser, wait for a bit, then come back and try again.

Edit: Emp beat me to it.