There is a video of the incident available from a local news station:NBC 29: Count on Us – Incident at Allen Campaign Stop in Charlottesville. The text accompanying the video states:
As Senator Allen was exiting a ballroom, coming to talk to the media, a protestor started yelling and asking, “Why did you spit on your first wife?”. He wasn’t able to get near the senator as he was tackled by three men wearing Allen stickers, presumed to be staffers. He was pushed and manhandled and ended up on the floor, near windows at the Omni.