Thanks for a quick response.
There are no error message displayed because, as far as php is concerned, there is no error. It's just calling a page that doesn't happen to exist. It happens in xcgal too incidentally.
The cache directory was set to 755. I've changed it to 777 but there's no change.
You mentioned 2 path definitions. I can only see one in mainfile.php. Where will I find the other . . . or is that the problem???
As this isn't yet a live site and I've only spent a couple of hours on it so far, I'm tempted to start again if I can't resolve it.
Thanks again.