C# - Late Binding In Child AppDomain - Develop A Plugin Architecture

I am trying to develop a plugin architecture in .Net. The application will be a .Net application. There will be directories which holds the plug-ins. Each directory will represent a plugin. Each plugin directory will also contain all the dependency dlls as well. The plugins need to be stored in separate AppDomain as the plugins may use the same assemblies, but different versions. As it iterates through the foreach loop in Init(), I get a System.IO.FileNotFoundException : Could not load file or assembly '[Assembly Name], Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.in _apDomain.Load() for assemblies that are not in the main project.

readonly private AppDomain _appDomain;
internal ItemModuleAppDomain()
{
AppDomainSetup info = AppDomain.CurrentDomain.SetupInformation;
_appDomain = AppDomain.CreateDomain("ChildDomain");
}
public void Init(string dllDir)
{
string[] dlls = Directory.GetFiles(dllDir, "*.dll", SearchOption.TopDirectoryOnly);
foreach(string dll in dlls)
{
_appDomain.Load(AssemblyName.GetAssemblyName(dll));
}