Unhandled Exception opening AutoCad

hi,
I am using the below mentioned code to open acad, _____________________________________
imports Autocad
Imports System.Runtime.InteropServices
Try
acadApp = Marshal.GetActiveObject("AutoCAD.Application")
Catch
Try
acadApp = New AcadApplicationClass()
Catch
Throw
End Try
End Try
_______________________________________

It worked fine however since yesterday it gives the following error. I created a new project and tried only this code to check if i have changed something in my project, but it still gives the same error. Here is the error.
______________________________________
An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in collection.exe
Additional information: Server execution failed
______________________________________

Can soomeone guide me please what is wrong and how to correct it.

Irfan

 

ignore this, i have sorted it anyway.
Acad licence file was no available on my system and therfore acad was not available.

irfan