hi Robert,
When this happened to me, recompiling that problem.prg with the check box ticked did the trick - i assumed that i must have had it unticked when that program was first compiled.
regards [trust someone else has the answer]

>hi andrew!
>
>thanks, but that is not the problem.
>
>as i said, only one program from the app displays this message 'source not available' - the other programs are ok, they accept break-points and show their source.
>
>therefore the app is compiled with debug info.