ARRGH: Audio folder for recording externally mixed audio in 5.1

[Lopp]

I posted this on www.cubase.net, but thought someone here may have input:

Summary:
In Cubase VST/32 5.1, when trying to record a mix sent out S/PDIF and returned via S/PDIF to two tracks (or a stereo track), I get a message something like "Please select folder for audio files."

However, under Options/Audio Setup/Audio Files Folder, I have already assigned a folder for audio files. (In fact, I had already recorded audio files earlier in the session, which I now wish to mix down).

Thus, Somebody PLEASE tell me what the hell Cubase is looking for.

The message window prevents me from recording and gives no error code or indication of where to make the appropriate settings!


More detailed description and background:

I have a song recorded which I wish to mix down.

I am mixing down via the S/PDIF out on a Delta 66, though a Finalizer Plus, and back in through S/PDIF.

I had to do extensive routings and dinking around in the audio inputs, Master mixer, assigning tracks to alternate busses to finally get a signal out and back without feeding back through the chain (which I eventually, later, found out was actually documented in the manual).

The audio tracks are assigned to an alternate buss for mixdown and output via S/PDIF. A stereo track is assigned to the S/PDIF inputs. The stereo track outputs to the master outputs.

Unfortunately, I can't record the signal coming back in through S/PDIF because Cubase requests a folder for audio files. (As an aside, I also cannot monitor the signal returning via S/PDIF, but I do see the signal on the assigned stereo track...)

Where is the menu selection for assigning the audio files (aside from Options/Audio Setup/Audio Files Folder)?


TIA for any suggestions.