Thanks for your reply.
It helped me a bit :)
When I use the Ax<>.dll lib now and set the thread to a STA, then I don't get the threading error anymore. And using the
TVicLPT2.CreateControl() line, prevented the InvalidActiveXStateException from coming up.
However, my interrupt handler...
I have got a question about AxInterOp and InterOp.
When I add a com control to my form, it automatically adds two references to my project; Ax<>.dll and <>.dll. After some research I found that the Ax-dll is the actual component used for the form (visibility) and VS automatically uses it...