-[__NSCFString count]: unrecognized selector sent to instance 0xba2ce80

[FBRequestConnection startWithGraphPath:@"/100000200918206/likes"
 parameters:nil
 HTTPMethod:@"GET"
 completionHandler:^(
 FBRequestConnection *connection,
 id results2,
 NSError *error
 ) {
 /* handle the result */
 if (error) {
 NSLog(@"Error: %@", [error localizedDescription]);
 } else {
 [self simIndex];
 }


 }];

-(void) simIndex {
 //...
}