[NSFileManager copyItemAtPath:toPath:error:]: source path is nil - objective-c

Question

I am trying to add a sqlite DB into an application using this: CoreData: Preload Data in Your iOS App
Following the tutorial i hit a problem:
[NSFileManager copyItemAtPath:toPath:error:]: source path is nil
I use the following code:
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (__persistentStoreCoordinator != nil) {
return __persistentStoreCoordinator;
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:#"Peter_R0_1.sqlite"];
if(![[NSFileManager defaultManager] fileExistsAtPath:[storeURL path]]) {
NSString *sqlitePath = [[NSBundle mainBundle] pathForResource:#"Peter_R0_1" ofType:#"sqlite" inDirectory:nil];
NSError *anyError = nil;
BOOL success = [[NSFileManager defaultManager] copyItemAtPath:sqlitePath toPath:[storeURL path] error:&anyError];
}
NSError *error = nil;
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
{
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return __persistentStoreCoordinator;
}
I would very much appreciate some help on this problem

Answer 1

Well, that error means the NSString *sqlitePath is == nil so 99% chance it's one or more of the following:
The file is not added to the correct Target in the project
Verify via "Target Membership" under the File Inspector view for the Peter_R0_1.sqlite file)
And/Or: You're copying the file to a specific sub-directory instead of the default.
Verify the file is listed under "Copy Bundle Resources" under your Target's "Build Phases" and NOT under "Copy Files" with a custom destination or sub-path.
And/Or: You've got a typo in the file name.