When using WS2008 x64 Ent. to host RC2, I use an "ISOs" datastore to access a network folder full of CD / DVD images. The datastore can be created and used, but after a host reboot, the store is inaccessible with the message:
"The Datastore Browser could not successfully retrieve data from the server."
I can re-create it and all works until the next reboot.