Failed to load data set

Hi Vuforia,

I am downloading .xml and .dat from server . 

My downloading method is:-

NSString *urlToDownload = @"https://s3.amazonaws.com/uploads.hipchat.com/122799/3164901/O7QFARbEJUbmEbo/shopping.xml";         NSURL  *url = [NSURL URLWithString:urlToDownload];         urlData = [NSData dataWithContentsOfURL:url];         if ( urlData )         {             NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);             NSString  *documentsDirectory = [paths objectAtIndex:0];             NSString  *xmlFilePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory,@"result.xml"];             NSLog(@"Downloading Started %@",xmlFilePath);             filePath = [xmlFilePath lastPathComponent];             //saving is done on main thread             [urlData writeToFile:filePath atomically:YES];         }

same for.dat.

I used :-

if (!dataSet->load([dataFile cStringUsingEncoding:NSASCIIStringEncoding], Vuforia::STORAGE_ABSOLUTE)) { }

I get error  "failed to load dataset".

Please help me asap.