OK, we checked across a few machines, and the problem only appeared on the one where we had SP2 installed on Dutch XP; it works OK on any other machine (and we run the same thing on server 2003, Vista, XP - all English and all with SP1).

The error manifests itself as several errors about temp files - either 'memo missing on invalid' or 'could not create file' or 'error writing...'. It was usually something about views - names of various tmp files would pop up. Further, it was an executable built with SP1 and run under SP2 runtimes.

After replacing the runtimes with SP1, it all went back to normal.

Just in case anyone else may experience the same problem. It seems that the runtimes and compiler version are bound more tightly than we thought.