Thanks for the stack trace. I would generally recommend to post it here directly as a code snippet instead of uploading pictures, as it would be easier to e.g. check it on a mobile device. 
I missed that you are already transforming the data to tensors, which would throw this error:
self.X = torch.Tensor(X)

transforms.ToTensor() should be applied on PIL.Images or numpy arrays. Since you already are dealing with tensors, you could skip this transformation.