bbotella:
Have you tried to redownload the IDE? Maybe there is some problem with it.
Thanks for replying and no I haven't. I hadn't thought of it, and it wasn't mentioned in the troubleshooting guide.
But I have now deleted the IDE and unzipped the original zip file, which I know was good because I used it for weeks without problems, and …
Voila! It works now! I spent all day yesterday wrestling with it, and it was something so simple. C'est la vie … and thanks again.