Unable to Buld & Run due to Unity Sprite Packer compiler error

As the title states, I can’t build and run my game client due to the following error:

ReflectionTypeLoadException: The classes in the module cannot be loaded.
System.Reflection.Assembly.GetTypes () (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Reflection/Assembly.cs:371)
UnityEditor.Sprites.Packer.<RegenerateList>m__DE (System.Reflection.Assembly a) (at C:/BuildAgent/work/d3d49558e4d408f4/Editor/Mono/Sprites/SpritePacker.cs:61)
System.Linq.Enumerable+<CreateSelectManyIterator>c__Iterator14`3[System.Reflection.Assembly,System.Type,<>__AnonType0`2[System.Reflection.Assembly,System.Type]].MoveNext ()
System.Linq.Enumerable+<CreateWhereIterator>c__Iterator1D`1[<>__AnonType0`2[System.Reflection.Assembly,System.Type]].MoveNext ()
System.Linq.Enumerable+<CreateSelectIterator>c__Iterator10`2[<>__AnonType0`2[System.Reflection.Assembly,System.Type],System.Type].MoveNext ()
System.Linq.Enumerable+<CreateSelectIterator>c__Iterator10`2[System.Type,System.String].MoveNext ()
System.Collections.Generic.List`1[System.String].AddEnumerable (IEnumerable`1 enumerable) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Collections.Generic/List.cs:128)
System.Collections.Generic.List`1[System.String]..ctor (IEnumerable`1 collection) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Collections.Generic/List.cs:65)
System.Linq.Enumerable.ToArray[String] (IEnumerable`1 source)
UnityEditor.Sprites.Packer.RegenerateList () (at C:/BuildAgent/work/d3d49558e4d408f4/Editor/Mono/Sprites/SpritePacker.cs:65)
UnityEditor.Sprites.Packer.GetSelectedPolicyId () (at C:/BuildAgent/work/d3d49558e4d408f4/Editor/Mono/Sprites/SpritePacker.cs:76)
UnityEditor.HostView:OnGUI()

The game will play within the editor without problem, however, when trying to build the client for external use, it simply stalls at building iwth this error. Suggestions?

Solved.

Solution:
Make sure that if you’re importing dll’s, that all dll’s referenced in the imported dll is included.

For example, our project has our own imported dll classes compiled with C# Visual Express 2010 .NET 2.0. One of these classes was referencing another dll for another library. In this case, I just removed that second referenced dll from the Visual Express project because I was only using it for testing, but had I wanted to use it, I would have also had to include that dll in the Unity project.