Consuming ActiveX in C#

[ColinR]

I need to use methods from a ActiveX control in c#.

1. I add a reference to the .dll.
2. I instantiate the class.
3. I call a method from the .dll.

at this point I get:

System.Runtime.InteropServices.COMException (0x8000FFFF): Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))
at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
at SpectivaWebLib.SpectivaWebClass.ConnectEx(String user, String passwd, String host, Int32 delta, Int16 keyFrameRefresh, Int16 bitRate, Int32 port)
at CamControl.Form1.button2_Click(Object sender, EventArgs e) in D:\Development\MMP\CamControl\CamControl\Form1.cs:line 131

What's broken