I went around in circles with this today as well.
I followed the steps, but the key for me was making sure EACH and EVERY file in the Recorded TV share had ANONYMOUS LOGON set for FULL control.
Even if the folder had all the rights, this wouldn't work. As an FYI for those like me that may not know, once you have the regedits done, event if you can't see the files from the WHS once you get the proper access they appear in the Recorded TV listing in Vista Media Center.
What would be the script for changing the batch file for setting all files in the folder to anonymous logon with full control. I think I am going to add that to the batch file so I don't have to do that again.
Would you add the /T call to the cacls line?
I was able to get Vista to accept the share \\server name here \Recorded TV to work. I also had the share mapped, but did not need to go that route.