I'm guessing that ArtioSEF is rewriting page titles with all pages with the same title: the title for the site. I'm using Joomla 1.0.13 + JoomSEF 2.2.6. What am I doing wrong???

Never mind! I found the setting and it wasn't ArtioSEF at all. I had set Global SEO settings to not to create dynamic page titles. All is okay now