Unable to load library issue with external dependencies - c++

Question

I have created a C++ *.dll in VS 2013. This runs fine on my development machine, however is throwing an error when run on a clients machine.
Here is the cpp file.
#include "stdafx.h"
#include "EasyDLL.h"
using namespace System;
double WINEXPORT EASYDLL_GetServerDateTime(int clientServerTimeDiff)
{
System::DateTime clientDateTime = System::DateTime::Now;
System::TimeSpan duration( 0, 0, clientServerTimeDiff );
System::DateTime serverDateTime = clientDateTime.Add( duration );
String^ strTemp = serverDateTime.ToString("yyyyMMddHHmmss");
double result = double::Parse(strTemp);
return result;
}
I believe the reason is, the external dependencies don't exist on the client's machine.
I don't have much experience with C++.
Lead up to question:
When you compile (and I'm just compiling in debug at the moment), there is a whole bunch of header files in the external dependencies and a dll (mscorlib.dll).
The mscorlib.dll exists in the same place on the client machine, so I'm kind of discounting that as the problem, but the headers do not exist.
Question:
Do I need to ship these headers off with the dll I've created or should they be compiled into my dll?
Here's a screenshot of some of the external dependencies. Most of them seem to be in the project by default when the project was created.
EDIT:
After changing the project to release it seems to be running on another machine as well as my dev machine, have to wait untill tomorrow to test on the client's.
Although it has worked so far, I checked out DependencyWalker and got the following when looking at my dll, is this anything to be worried about?

Answer 1

You don't need to ship the headers with the DLL. If Mats answer doesn't solve it you might want to try using this tool: http://www.dependencywalker.com/
You can "look inside" a DLL that way. From my experience, best run it on both machines i.e. on the dev machine and the client machine because what might look like an error on the client machine, may also exist on the dev machine, thus discounting it as the problem.
Good luck!