Keith,
Thank you very much.
Alas, only half solved the problem, I'm afraid.
I changed the settings from 16 bit to 8 bit (since this was the first time I had ever tried to create Jpegs using ACR - I usually use Image Processor in CS3 - it had been set to 16 bit by default) and then selected 10 images for conversion. Worked fine.
I then tried another 10 and, on the last one, the same error message window reappeared. So, I tried a smaller number of images. Same problem, only this time it appeared on the first image. i.e. no image was converted at all. i.e. the problem had been working its way back in and was fully there on the 15th or 16th image. Very like a cache problem, I thought.
So, I closed and reopened Bridge and purged the cache for that folder. Still no joy.
I can convert any number of tiffs or DNGs without a memory problem. What is going on with Jpegs?
Very annoying.
D.
Update:
I just ran a folder of 134 Canon Mk3 images through Jpeg conversion and it flew through them.
For some reason, ACR doesn't like converting my Hasselblad images. Anyone know why this might be?