Archiving Sessions--what does this message mean?

Hi All, I've always archived sessions to DVD-R. However, for the first time, PT does not enable reading these sessions off the DVDs and insists on copying the info to a hard drive to open them. Here is the message I am getting: This session is saved on a volume set to 'transfer' only. If permitted, set the volume in question to 'p' (playback) or 'r' (record) for the workspace. Otherwise, save a copy to a valid playback volume. The session copy will automatically open from the chosen location. Okay, is there a way to do the 'if permitted' tasks? I'd prefer to be able to open the archived sessions direct from DVD and not have to use free hard drive space just for a playback. Your thoughts? Any help appreciated, J.D

A CD or DVD is not fast enough for multitrack playback. Rail

You may have had some other kind of thing working, but not playing a session off the DVD. Maybe you had a session file on DVD while the original audio tracks were still on the hard disk, and PT happened to make the right connections filewise. But PT will not run a session from a CD or DVD so you will need to copy all to your audio drive.