need help

I've been making movie icons from DVDs but I everytime I try and make an icon from an avi movie I can't get my frames. I tried screencapping on wmp but when I try to paste all I get is an empty player window. I tried importing frames with animation shop but I keep getting 186 frames of the same image (I've tried every single option). I tried using virtual dub but it did the same thing. I don't know what else to try. Can anyone help me???