I suppose your data is of the wrong shape. Caffe expects a 4D blob at the input, made of (batch_size) of 3D blobs. I'm not sure about HDF5 labels though, I suppose they can be anything up to that size, but also follow that scheme: 1-, 2-, or 3D data piece, batched along another dimension. That error seems to suggest that your input has too few dimensions and caffe doesn't know how to convolve with it... as if you had a 2D blob instead of 4D, hence a 1D "image" to work with. Are you sure your data is 3D, in this case 1x1x3000, instead of 1D (just 3000)? I think it should be.