Thanks to all who replied online and offline. The problem is now solved. For the benefit of others who might encounter a similar problem, it might be worth explaining the solution.
The FM files are stored in a source-control system. For OS compatibility reasons, I had FrameMaker 7.2 and my local copy of the FM files on a virtual disk managed by Microsoft Virtual PC. When I moved the files to a physical disk, the problem disappeared. Likewise, the problem disappeared when I left the files on the virtual disk and compacted the disk. It seems possible that the problem was caused by disk corruption. I can't be sure of this, however. In all other respects, the virtual disk worked fine. The disk passed diagnostic tests without error. I have worked in FrameMaker in the virtual environment for approximately two years with no previous problem. At regular intervals, I defragment the physical disk and the virtual disk, and I compact the virtual disk. In any event, I moved my local workspace to the physical disk, and all is well. FrameMaker remains on the virtual disk. David Shaked (Wernick) AlmondWeb Ltd. http://www.almondweb.com Technical Documentation * Web Development * Word and WebWorks Consultants