As the error message explains, nn.Embedding expects indices as its input (as LongTensor or IntTensor), while you are passing FloatTensors to it.
Note that an embedding is working as a “lookup table” and outputs dense feature tensors.
Based on your input you also won’t be able to simply transform the input to a LongTensor, since it contains negative indices (besides the obvious rounding, which I don’t know if it would fit your use case).