Can you help me,I have one Error! please!

when I start
!CUDA_VISIBLE_DEVICES='0' python -u train_softmax.py --network r100 --loss arcface --dataset emore

I have one Error:
config.imageshape: 3
prefix ./models/r100-arcface-emore/model
image_size [112, 112]
num_classes 4
Called with argument: Namespace(batch_size=16, ckpt=2, ctx_num=1, dataset='emore', frequent=20, image_channel=3, kvstore='device', loss='arcface', lr=0.01, lr_steps='100000,160000,220000', models_root='./models', mom=0.9, network='r100', per_batch_size=16, pretrained='../models/arcface_r100_v1/model', pretrained_epoch=0, rescale_threshold=0, verbose=2000, wd=0.0005) {'bn_mom': 0.9, 'workspace': 256, 'emb_size': 512, 'ckpt_embedding': True, 'net_se': 0, 'net_act': 'prelu', 'net_unit': 3, 'net_input': 1, 'net_blocks': [1, 4, 6, 2], 'net_output': 'E', 'net_multiplier': 1.0, 'val_targets': ['lfw', 'cfp_fp', 'agedb_30'], 'ce_loss': True, 'fc7_lr_mult': 1.0, 'fc7_wd_mult': 1.0, 'fc7_no_bias': False, 'max_steps': 0, 'data_rand_mirror': True, 'data_cutoff': False, 'data_color': 0, 'data_images_filter': 0, 'count_flops': True, 'memonger': False, 'loss_name': 'margin_softmax', 'loss_s': 64.0, 'loss_m1': 1.0, 'loss_m2': 0.5, 'loss_m3': 0.0, 'net_name': 'fresnet', 'num_layers': 100, 'dataset': 'emore', 'dataset_path': '../src/data/dataset/4sv', 'num_classes': 4, 'image_shape': [112, 112, 3], 'loss': 'arcface', 'network': 'r100', 'num_workers': 1, 'batch_size': 16, 'per_batch_size': 16}
loading ../models/arcface_r100_v1/model 0
[04:50:10] src/nnvm/legacy_json_util.cc:209: Loading symbol saved by previous version v1.0.0. Attempting to upgrade...
[04:50:10] src/nnvm/legacy_json_util.cc:217: Symbol successfully upgraded!
0 1 E 3 prelu False
config.loss_name: margin_softmax
config.loss_s: 64.0
Network FLOPs: 24.2G
mx.gpu(): gpu(0)
triplet <= 0.
INFO:root:loading recordio ../src/data/dataset/4sv/train.rec...
loading idx... ../src/data/dataset/4sv/train.idx
Traceback (most recent call last):
File "train_softmax.py", line 480, in
main()
File "train_softmax.py", line 476, in main
train_net(args)
File "train_softmax.py", line 332, in train_net
images_filter=config.data_images_filter
File "/content/drive/My Drive/khoaluantn/recognition/image_iter.py", line 40, in __init__
s = self.imgrec.read_idx(0)
File "/usr/local/lib/python3.7/dist-packages/mxnet/recordio.py", line 317, in read_idx
self.seek(idx)
File "/usr/local/lib/python3.7/dist-packages/mxnet/recordio.py", line 279, in seek
pos = ctypes.c_size_t(self.idx[idx])
KeyError: 0