NSArrayController troubles

[robertcerny at mac.com (Robert Cerny)]

Hi folks,
I'm trying to implement bindings into already finished application and 
have got two problems:
a] Exception raised during posting of notification.  Ignored.  
exception: *** -[NSCFArray objectAtIndex:]: index (-1) beyond bounds 
(0)
I created a model, which contains just NSString *name variable. 
Following the samples from Apple and mmalc I made it an object class 
name of NSArrayController. I also added "Add" and "Remove buttons" but 
get an exception them. The exception is raised after clicking the first 
row of table.

b] I'm not really sure how to combine datasource and binding. I have 
some data coming from directory enumerator, which runs in the second 
thread. How can I use it as an source for NSArrayController? I checked 
the docs, and - (void)addObjects:(NSArray *)objects looks like a good 
candidate, but am I right?

Thanks a lot
Robert