Totally agree with Eric on this one. This movie reminds me more of an episode on some random sitcom. Nothing much happens and the characters don't go too deep.
"What I saw was a vulnerable young woman desperately in search of some kind of fulfillment."
Her character was just to shallow to portray any real vulnerability. Crudup was a dud. The seen you describe him tripping sums it up. As he is the focal point of the movie, this is the weakest part. I would not recommend this movie.

Patrick, Penny Lane dehumanizes herself. People will treat you as you present yourself. She may be "a vulnerable young woman desperately in search of some kind of fulfillment." but all the band memebers see is a slut. If she wanted to be treated differently, she should presented herself differently.