The ntdll.dll error comes under many programs and their cause is different in each case. Especially while running a very old program/software/game with new versions of x64-bit type Windows may pop-up this error.
Here the Developer Studio in Compaq visual fortran v6.x calls this file(ntdll.dll) directly from Windows for Native application interface. This file has been heavily patched in Windows Vista and 7 due to underlying vulnerability and security risks in earlier versions of Windows (NT, Xp) and so it does not provide full functionality over other software which handles it before and hence the application crashes. Now a days many Windows applications and software vendors incorporate Native application libraries within their products rather directly calling from windows.
1. Change the compatibility mode to Earlier versions of Windows and set Privilege level to Administrator.
2. Disable User account control in Windows Vista and 7.
3. Disable Program Compatibility Assistant in Windows Vista and 7.
Note: This error cannot be fixed in cases like if you are using 2nd or 3rd Generation CPU's (i3/i5/i7) regardless of Windows Vista/7 (x86/x64 bit).