Issue in C# PresentationFramework.DLL while Sandbox Enable

I have C# DLL which load PresentationFramework.dll .I call it from Acrobat SDK -> Basic Plugin in Acrobat Pro cd.
It works normally without any issue, but when acrobat run on sandbox enable it throws this exception
"Unspecified error (Exception from HRESULT: 0x80004005 (E_FAIL)"

This is the code to call the DLL from the basic plugin "BasicPlugin.api"

_declspec(dllexport) void TestLoadDLL();
ACCB1 void ACCB2 MyPluginCommand(void *clientData)
{
	TestLoadDLL();
}

This is the code in the C#  "ManagedCSharp.dll"

 String executablePath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
            try
            {
                Assembly.LoadFile(System.IO.Path.Combine(executablePath, "PresentationFramework.dll"));  
            }
            catch (Exception ex)
            {
                string error = "PresentationFramework.dll";
                do {
                    error += Environment.NewLine + ex.Message;
                    error += Environment.NewLine + ex.StackTrace;
                    ex = ex.InnerException;
                } while (ex != null);
                MessageBox.Show(error);
            }