Trouble using Mex file for external window switching

Here is a matlab code that employs ctrlWindow.mexw64 file.

In the code below, Window Name 1 is generated by program1.exe. Window Name 2 is generated by MATLAB GUI. When I click F9 after selecting the entire code, I am able to see windows getting switched. works great. But on the same code, when I do F5 (run), there is window identification issue. MATLAB throws an error message "can not find the window!!!". Any thoughts? One more clue : The mex file is generated in R2012a and I am using it in R2010a. The code work either ways in R2012a system.

% code begins

!program1.exe

ctrlWindow('Window Name 1',3); % this maximizes this window

pause(1)

ctrlWindow('Window Name 1',0); % this hides the window

pause(1)

ctrlWindow('Window Name 2',3); % Maximizes

pause(1)

ctrlWindow('Window Name 2',0); % hides

pause(1)