Cannot Set NSMutableSet as Value for PFObject Key in Parse - objective-c

Question

Whenever run the below code in my IOS app, it just magically stops running when I make a NSMutableSet a value for a PFFobject Key (line marked with "TROUBLE" below). If I put a break point, the computer just doesn't get to the next break point. I even added a column in my Parse dashboard, where "peopleWhoFavorited" is an Object type, the problem still occurs. Why? Code:
BOOL POSTING; //prevents repitious saving when user presses button multiple times.
-(void)post {
if (!(self.data==nil) && ![self.postField.text isEqualToString:#""] && !POSTING && ![self.postField.textColor isEqual:[UIColor grayColor]]) { //hackey with that grey color, but oh well.
POSTING=YES;
PFFile *file = [PFFile fileWithName:#"data" data:self.data];
[file saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
if (succeeded) {
PFObject *post = [PFObject objectWithClassName:#"post"];
[post setObject:#(0) forKey:#"voteScore"];
[post setObject:#(0) forKey:#"numTimesReported"];
[post setObject:#[] forKey:#"whoReported"];
[post setObject:#[] forKey:#"comments"];
//And now, the favorited sets and upvote and downvote sets...
NSMutableSet * favoritedSet=[[NSMutableSet alloc] init];
[post setObject:favoritedSet forKey:#"peopleWhoFavorited"]; "TROUBLE" //magical stopping point
NSMutableSet * peopleWhoUpVoted=[[NSMutableSet alloc] init];
//[post setObject:peopleWhoUpVoted forKey:#"peopleWhoUpVoted"];
NSMutableSet * peopleWhoDownVoted=[[NSMutableSet alloc] init];
//[post setObject:peopleWhoDownVoted forKey:#"peopleWhoDownVoted"];
//
//And a set for the people who report the post.
NSMutableSet * peopleWhoReported=[[NSMutableSet alloc] init];
//[post setObject:peopleWhoReported forKey:#"peopleWhoReported"];
//
[post setObject:self.postField.text forKey:#"postName"];
[post setObject:self.dataTypeString forKey:#"postType"]; //either a movie or an image
[post setObject:[NSDate date] forKey:#"dateMade"]; //hackey, equivalent of createdAt to avoid weird behaivor
[post setObject:file forKey:#"data"];
NSString * deviceIDString=[[[UIDevice currentDevice] identifierForVendor] UUIDString];
[post setObject:deviceIDString forKey:#"deviceThatPosted"];
[PFGeoPoint geoPointForCurrentLocationInBackground:^(PFGeoPoint *geoPoint, NSError *error) {
if (!error) {
// set the location of the post.
[post setObject:geoPoint forKey:#"location"];
//save the post in the background
[post saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
if (succeeded) {
NSLog(#"Saved.");
[self dismissViewControllerAnimated:YES completion:^{
NSLog(#"Posted and Dismiss completed");
}];
POSTING=NO;
} else {
NSLog(#"%#", error);
POSTING=NO;
}
}];
} else{
NSLog(#"%#", error);
POSTING=NO;
}
}];
} else {
NSLog(#"%#", error);
POSTING=NO;
}
}];
}
}