Hi, I am getting same error. Here is the traceback. Also I am able to iterate the full dataset without any exceptions as suggested by @ptrblck  above.
Traceback (most recent call last):
  File "iBatchLearn.py", line 150, in <module>
    acc_table, task_names = run(args)
  File "iBatchLearn.py", line 78, in run
    agent.learn_batch(train_loader, val_loader)
  File "/home/shivam/ssaboo2020/Continual-Learning-Benchmark/agents/exp_replay.py", line 39, in learn_batch
    super(Naive_Rehearsal, self).learn_batch(new_train_loader, val_loader)
  File "/home/shivam/ssaboo2020/Continual-Learning-Benchmark/agents/default.py", line 222, in learn_batch
    self.validation(val_loader)
  File "/home/shivam/ssaboo2020/Continual-Learning-Benchmark/agents/default.py", line 115, in validation
    for i, (input, target, task) in enumerate(dataloader):
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/torch/utils/data/dataloader.py", line 345, in __next__
    data = self._next_data()
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/torch/utils/data/dataloader.py", line 838, in _next_data
    return self._process_data(data)
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/torch/utils/data/dataloader.py", line 881, in _process_data
    data.reraise()
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/torch/_utils.py", line 394, in reraise
    raise self.exc_type(msg)
IndexError: Caught IndexError in DataLoader worker process 1.
Original Traceback (most recent call last):
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/torch/utils/data/_utils/worker.py", line 178, in _worker_loop
    data = fetcher.fetch(index)
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/torch/utils/data/_utils/fetch.py", line 44, in fetch
    data = [self.dataset[idx] for idx in possibly_batched_index]
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/torch/utils/data/_utils/fetch.py", line 44, in <listcomp>
    data = [self.dataset[idx] for idx in possibly_batched_index]
  File "/home/shivam/ssaboo2020/Continual-Learning-Benchmark/dataloaders/wrapper.py", line 51, in __getitem__
    img,target = self.dataset[index]
  File "/home/shivam/ssaboo2020/Continual-Learning-Benchmark/dataloaders/wrapper.py", line 81, in __getitem__
    img,target = self.dataset[self.indices[index]]
  File "/home/shivam/ssaboo2020/Continual-Learning-Benchmark/dataloaders/wrapper.py", line 33, in __getitem__
    img,target = self.dataset[index]
  File "/home/shivam/ssaboo2020/Continual-Learning-Benchmark/dataloaders/custom_datasets.py", line 22, in __getitem__
    img = Image.open(self.df['PATH'].iloc[index])
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/pandas/core/indexing.py", line 1500, in __getitem__
    return self._getitem_axis(maybe_callable, axis=axis)
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/pandas/core/indexing.py", line 2230, in _getitem_axis
    self._validate_integer(key, axis)
  File "/home/shivam/ssaboo2020/incremental/lib/python3.5/site-packages/pandas/core/indexing.py", line 2139, in _validate_integer
    raise IndexError("single positional indexer is out-of-bounds")
IndexError: single positional indexer is out-of-bounds