Cetin,
Thanks for your reply! There is no config.fpw, and here's the trick with the project:
When I run the application at the command line, with DO main.prg (as opposed to DOing the .app), I still get the error at various places.
Once, when I removed a MODIFY WINDOW xxx FONT xxx command, the errors stopped, but then for no reason, they started again. Very confusing!
Mark

>Mark,
>In config.fp(w) and project file (app.pjx) check for a reference to a nonexistant drive.
>Cetin