C# .Net ApplicationManager.GetEngine() throws an exception

Hello,

I'm developping a .Net application using TestStand API.

Here are my initializing commands :

private AxApplicationMgr applicationManager = new AxApplicationMgr();

private static Engine engine = applicationManager.GetEngine();

The second line worked only once, but now it throws an InvalidActiveXStateException.

Do you know what this could mean ?

Thank you.