I’m having the same issue, trying to upgrade from 3.0.3 to 3.0.5. I managed to upgrade all the plug-ins (some had to be deleted and re-installed to get the latest versions), but still can’t upgrade WordPress. In re-reading the docs, I’m not sure the upgrade is really that significant, as I’m not having any problems. Certainly doesn’t appear to be worth the problem of a manual upgrade, considering the research I’d have to do so as not to lose everything I’ve already got. Would you agree?