import failure for Admob library on Eclipse for Android

I am trying place a banner ad from Admobs on my Android app and I receive the following error when I run my program

"com.google.ads.AdView failed to instantiate."

The program installs on the emulator and functions properly but because of this error my banner never displ开发者_运维百科ays. I've tried importing the library through both of these lines (not simultaneously).

import com.google.ads.*;
import com.google.ads.AdView;

Yet I continue to get the instantiation failure... Any advice? Thanks ahead of time.

Try cleaning your project, often times files get messed up when its building automatically.