Desktop I'm Using Unity 5.4.0b19 (64-bit) and When I developed with SteamVR I Got this

Unhandled Exception: System.Reflection.ReflectionTypeLoadException: The classes in the module cannot be loaded.

at (wrapper managed-to-native) System.Reflection.Assembly:GetTypes (bool)

at System.Reflection.Assembly.GetTypes () [0x00000] in <filename unknown>:0

at Mono.CSharp.RootNamespace.ComputeNamespaces (System.Reflection.Assembly assembly, System.Type extensionType) [0x00000] in <filename unknown>:0

at Mono.CSharp.RootNamespace.ComputeNamespace (Mono.CSharp.CompilerContext ctx, System.Type extensionType) [0x00000] in <filename unknown>:0

at Mono.CSharp.GlobalRootNamespace.ComputeNamespaces (Mono.CSharp.CompilerContext ctx) [0x00000] in <filename unknown>:0

at Mono.CSharp.Driver.LoadReferences () [0x00000] in <filename unknown>:0

at Mono.CSharp.Driver.Compile () [0x00000] in <filename unknown>:0

at Mono.CSharp.Driver.Main (System.String[] args) [0x00000] in <filename unknown>:0

The following assembly referenced from D:\U3dProject\GodMayCry\EvilMayCry\Assets\Plugins\UnityPurchasing\Bin\Stores.dll could not be loaded:
Assembly: UnityEngine.Purchasing (assemblyref_index=1)
Version: 0.0.0.0
Public Key: (none)
The assembly was not found in the Global Assembly Cache, a path listed in the MONO_PATH environment variable, or in the location of the executing assembly (D:\U3dProject\GodMayCry\EvilMayCry\Assets\Plugins\UnityPurchasing\Bin\).

Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The class UnityEngine.Purchasing.IAmazonExtensions could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The class UnityEngine.Purchasing.IAmazonExtensions could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The class UnityEngine.Purchasing.IGooglePlayConfiguration could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class UnityEngine.Purchasing.NativeJSONStore could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The class UnityEngine.Purchasing.IAppleConfiguration could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class UnityEngine.Purchasing.IAppleExtensions could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The class DialogType could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The class MicrosoftConfiguration could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class UnityEngine.Purchasing.FakeStore could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class DialogRequest could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class LifecycleNotifier could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
Could not load file or assembly 'UnityEngine.Purchasing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The class <MessageCallback>c__AnonStorey0 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <RetrieveProducts>c__AnonStorey0 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <Purchase>c__AnonStorey1 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <StartUI>c__AnonStorey0`1 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <OnProductListReceived>c__AnonStorey0 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <log>c__AnonStorey1 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <OnPurchaseFailed>c__AnonStorey2 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <OnPurchaseSucceeded>c__AnonStorey3 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null
The class <OnProductListError>c__AnonStorey4 could not be loaded, used in Stores, Version=1.0.5974.32831, Culture=neutral, PublicKeyToken=null


And the Inspector Looked like this:
I just wanna report this error,and I'm downloading B22 to rebuild the project.

 

Could you provide a bug report with perhaps a minimal project attached to make it easier to repro?

Please report the bug # here if you could.