I use WordPress on a regular basis. I have it installed on many of my websites. I just installed a fresh copy of WordPress 3.5 on a new domain and only changed the permalink to Post Name or /%postname%/ and it broke the site. If I leave it on default, it works, but I don't want my site to have ?p=123 on all of my pages. I will have about 300-500 pages on this site.
If I change the permalink structure to anything other than default, it breaks the site and gives me a 404 error page.
Can someone please help me with this issue? If I leave this site this way when it goes live, I will certainly will never hear the end of it by my client.