Problems when building, DLLs missing?.. (Assembly-CSharp.dll)

I have included System.Data so that I can easily parse XML data. I copied the DDL from Unity\Editor\Data\Mono\lib\mono\2.0 to my projects Asset folder.

The project works fine in the editor, but complains when I try to build it (web or Windows standalone);

> ArgumentException: The Assembly
> System.Security is referenced by
> System.Configuration. But the dll is
> not allowed to be included or could
> not be found.

So I went ahead and copied System.Security.dll in the same way… repeated this untl for a few other System. dlls. Until I came across this:

Exception:

Error building Player: Failed copying dll into build Library/ScriptAssemblies/Assembly-CSharp.dll
UnityEditor.BuildPlayerWindow.BuildPlayerWithDefaultSettings (Boolean askForBuildLocation, BuildOptions forceOptions) (at C:/BuildAgent/work/6bc5f79e0a4296d6/Editor/Mono/BuildPlayerWindow.cs:341)
UnityEditor.BuildPlayerWindow.GUIBuildButtons (Boolean enableBuildButton, Boolean enableBuildAndRunButton, Boolean canInstallInBuildFolder) (at C:/BuildAgent/work/6bc5f79e0a4296d6/Editor/Mono/BuildPlayerWindow.cs:942)
UnityEditor.BuildPlayerWindow.ShowBuildTargetSettings () (at C:/BuildAgent/work/6bc5f79e0a4296d6/Editor/Mono/BuildPlayerWindow.cs:923)
UnityEditor.BuildPlayerWindow.OnGUI () (at C:/BuildAgent/work/6bc5f79e0a4296d6/Editor/Mono/BuildPlayerWindow.cs:697)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.

At which point I started to think I might have missed a step or two.

Can anyone point me in the right direction? As I said, I simply wanted to use .NET xml parsing functionality…

If you need XML parsing, just ask. :smiling_face: