If you can't delete recent posts, it's because your account is yet to be moved into a rebuilt permissions system; this should be complete tomorrow.
There is a time limit which prevents older posts being edited or deleted, but that's nothing new. It's primarily for reasons of performance - we (Admins & Mods) are happy to make changes to older posts when it's important, but edit/delete being available site-wide indefinitely causes quite a heavy overhead in re-indexing of posts for things like search & stats.
I've got a bit more testing to do (probably in the morning now), but any issues with recent posts and profile stuff will be cleared up tomorrow (today).
R