However, most ntdll.dll errors result from a corrupt or damaged version of the ntdll DLL file itself, corrupt hardware drivers, or issues between Windows and other programs. Ntdll.dll errors can sometimes mean that a piece of hardware in your computer is malfunctioning, but this is rare.
ntdll.dll is a module that contains NT system functions. The ntdll.dll file is a file created by Microsoft that has a description of NT Layer DLL" and is the file that contains NT kernel functions. This file is located in the c:\windows\system32 or c:\winnt\system32 directory and can also be found in the c:\i386 directory."