Hi Erich,
"Cheer up, they said - things could be worse. So I cheered up and things got worse."
Before sending you my project I thought I would create a new project and see what happened. This time I got about 10 errors._
"Cannot find xxx.h" where xxx was a ProcessorExpert component. At this stage I thought that CW was gradually destroying itself. Then I tried to run an example project and got the original error.
I then uninstalled CW 10.7, rebooted Windows and reinstalled CW. After a bit of tidying up I now have everything working. I have not yet installed the 10.7 service pack and I may reinstall CW 11 (just to be safe).
Finally, thanks for your help.