Problem with Kodak Image control

Hi all
    I am using Kodak Image Admin control in my project to find out tiff imge height and width. But the problem is when I run the program its throw an exception like

"An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll

Additional information: Catastrophic failure"

My code is ,

AdminLibCtl.ImgAdmin img=new AdminLibCtl.ImgAdminClass();
            img.Image=txtfilename.Text;
            int j=img.PageCount;
Plzz help me