>>The only my guess is that for some reason your application cannot see the directory where this prg file resides. In your onerror routine check whether this directory is in the application set(“path”) , and if it is there, then check for existence of this file.
>
>The directory exists and so does the file. The only thing that doesn't exist is the drive. The correct drive and directory is on the path.

You answered so quickly, and I am sort of puzzled: could you confirm here that after my last reply you modified your onerror routine in the application, then you rebuilt your application, and distributed it; and the client got an error you are talking about, and your onerror routine made a log file where among other information, the set(“path”) and the value of file() is documented exactly when the error occured? Could you show here all what is in this onerror log file?