I've just created a new WordPress blog and already I have a bit of an issue. When using a permalink structure that looks like so:
it doesn't work, it takes me to a 404 error. So instead of using this custom structure, I used one of the defaults. Long story short, any permalink structure that isn't THE default, "/?p=123" won't work. I'm thinking the problem lies in there being a confusing somewhere and the server mistaking
/%author%/%category%/%year%/%monthnum%/%day%/%postname% for actual directories.