Cannot access #include files – “permission denied” [modified]

I have downloaded IVT library ( Integrating Vision Toolkit), I made my app dependent on this library ( as DSP project in VC6.0) , I can partially compile the app because I get “permission denied” when I get to #include preprocessor statement.
I have checked the directory permissions and I have grayed out “read only” checked in IVT directory.
All of the sources I used so far said that such   grayed out “read only” checked ( in XP) does not make any difference (?)   when directories are involved.
All of my app directories have that grayed out “read only” checked and I have no problem including   other (OpenCV) libraries.
I am tempted to recopy / re-download the IVT files , but would like to hear from the forum what is going on here.
Appreciate any advise.
Cheers
Vaclav
 
Addendum
Here is the real code snippet
I must be doing something really stupid.
 
#pragma message("include IVT ")
#include <Z:\ProgramFiles\IVT\ivt-1.3.19\IVT\src> // fails
#include <Z:\ProgramFiles\IVT\ivt-1.3.19\IVT\src\Calibration> // fails
#include <Z:\ProgramFiles\IVT\ivt-1.3.19\IVT\src\Calibration\Calibration.h> // OK