We've gone through the upgrade steps for 0.10beta. At first, when we went to the site, we got a message saying we needed to install Omeka. Clicking the link took us to a page that said we could delete the install directory. But there was not way to continue. We either got one of those two pages or the other.
After deleting the install directory, we then just got the need-to-install page, nothing else.
So I replaced the install directory and now we get the need to install page, followed by a page with a message saying that "Apache's mod_rewrite extension must be enabled."
Well, when we restore all our old Omeka files, everything works fine under the old version. So the server environment must be OK. Can't figure this out. Here is an installation of the new version:
And here is the old version, on the same server, working fine:
These are both on Dreamhost.