new pc fresh copy of nero 6, thought i had all the right updates installed but got this error when trying to add the video file to nero??

Unable to add C:\Documents and Settings\dean\My Documents\MOVIES\Blade III - Trinity 2005 (1CD Telecine Repack By T-Boy - Superb Quality Almost DVD).avi to your project, the file is not valid or no decoder available.

WHAT DO I NEED?