[Dx4win] QSO Window Problem

[Ted Drake]

I have been using DX4WIN 7.03.16 for many months now without problem.  Suddenly a quirk has developed, and I need help please. 

 Now, as I open DX4WIN, all windows open as prearranged except my main QSO window. Instead, I am now getting an ERROR window on startup which says:
 
"Master file:     C: Program Files\dx4w703A\DX4WIN.MAS  not found, no calls loaded "

If I click on OK ...or Exit X, this ERROR window goes away and my QSO window opens for use.

Can someone please tell me why this is happening, and how to fix?  Many tnx....Ted, N8GZ