Archiving format change creating issues

I have chosen to change the archiving format from the default (/?post=2) to the time/topic format (/2006/15/10/example-post). But when I click on the post in the main page, it gives me a 404 page. I kow this will correct itself on future posts, but not on the last couple (I just started my blog so I only have 2 posts). Obviously I need to change ow that links up, but I cannmot find the page in the WordPress editor or in any of the files in my server. Sorry for the newb ignorance; I’m sure I’ll slap my forehead when given the solution.