WordPress MU

I've just spent hours searching for an answer with no luck. Maybe someone can help...

I have a new installation of WPMU 2.7. Images that I upload to the Media Library (using either the Flash or regular uploader) are accepted and the library lists them, but nothing actually gets uploaded.

The Library shows images are in /wpmu/blog/2009/05/04/51/, but there is no such folder. There is an empty blogs.dir folder, and when I try to set permissions to 777 (something I really don't want to do), the permissions don't get set.

Some "solutions" say to look at the Admin settings/Misc. section, but there is no such thing. I've looked all over and I don't see any setting that governs uploads.

Only odd thing I can think of is that I've set the blog to be visible only to administrators. (Once the site is ready, I will remove that restriction.) There's also no Google or Amazon plug-in installed. All the plug-ins that are installed are also installed on other servers running 2.7 and there are no such problems.

"The Library shows images are in /wpmu/blog/2009/05/04/51/, but there is no such folder. There is an empty blogs.dir folder, and when I try to set permissions to 777 (something I really don't want to do), the permissions don't get set."

This is the actual issue. The directories aren't getting created. You need to fiddle with permissions/ownership until they do.

You're probably right. This is the eighth WPMU installation I've done, and haven't had this problem before. What should the permissions be for the wpmu/blog folder? All the other folders are 755, so isn't that sufficient permission to create new folders?

Depends on who owns the folders and who is creating them (who according to the serve,r not WPMU)