我正在使用 CRM 插件注册工具将自定义活动加载到我们的 CRM 服务器上。我的自定义活动扩展System.Activities.CodeActivity。但是，每当我尝试注册程序集时，都会出现以下错误：
Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'System.Activities, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
at System.Reflection.Assembly._GetExportedTypes()
at System.Reflection.Assembly.GetExportedTypes()
at PluginRegistrationTool.AssemblyReader.RetrievePluginsFromAssembly(String path) in C:\Users\sblessing\Desktop\sdk\tools\pluginregistration\AssemblyReader.cs:line 60
at PluginRegistrationTool.AssemblyReader.RetrievePluginsFromAssembly(String path)
at PluginRegistrationTool.RegistrationHelper.RetrievePluginsFromAssembly(String pathToAssembly) in C:\Users\sblessing\Desktop\sdk\tools\pluginregistration\RegistrationHelper.cs:line 49
at PluginRegistrationTool.PluginRegistrationForm.btnLoadAssembly_Click(Object sender, EventArgs e) in C:\Users\sblessing\Desktop\sdk\tools\pluginregistration\PluginRegistrationForm.cs:line 127
我需要在哪里复制我的程序集才能消除此错误？
谢谢！