itunes is not sharing (or anything else) properly

iTunes is really beginning to bum me out to the highest level of bumtivity.

I have a MacMini running OS X 10.7.3 (fully updated). I run iTunes on it and it acts as a sort of media server for me. Until recent iTunes updates it's worked flawlessly.

I could watch movies on my iPad streamed from the MacMini.

I could watch movies on my iMac streamed from the MacMini.

I could watch movies on my iPhone streamed from the MacMini.

I could watch movies on my 50" flat screen through my AppleTV, streamed from the MacMini.

(I know it's technically not streaming, but caching the movies, but you know what I mean.)

It all worked great.

Now I've got nothing but problems.

I just bought and downloaded Mission Impossible Ghost Protocol.

AppleTV says I need to authorize the Mac to play the movie.

The MacMini is freaking authorized. So I authorize it again and it says it's already authorized. This goes on and on round and round and I eventually give up. This used to work perfectly.

I've got the newsest AppleTV also.

So I go sit at my desk and get ready to watch the movie through my iMac through the shared iTunes library.

First I have to quit iTunes on the MacMini and start it in order for the iMac to finally get a list of movies. (This is all wired EtherNet).

Then when I finally get the list of movies and select MI Ghost Protocol, the movie is plagued with stalls. My network is all gigabyte EtherNet. I ping a zillion packets to the MacMini and never drop a single one. This isn't a network problem.

No problems with the Roku of course. AppleTV streams NetFlix just fine, so does everything else on my network. It's just that homesharing has gone to **** in a handbasket. Count me in, in the growing number of people who really want to see iTunes completely redesigned from the ground up because it's a mess right now.

Has anyone else had these problems?

Thanks.