I'm trying to insert new records via data loader but I keep getting an error message saying 'Index 100 out of bounds for length 100' and the upload stops part way through, after some records have successfully uploaded.  Does anyone know what this error means? 
 

I have recently downloaded data loader and I am trying to update the batch size settings to 20 instead of 200, however there is no save button to actually update the batch size to 20, meaning it just stays on 200. Can anyone help / has anyone else had this? (screenshot attached). I have tried downloading and reinstalling it but there is still no save button, even when I scroll to the bottom. 

I'm trying to insert new records via data loader but I keep getting an error message saying 'Index 100 out of bounds for length 100' and the upload stops part way through, after some records have successfully uploaded.  Does anyone know what this error means? 
 

I have recently downloaded data loader and I am trying to update the batch size settings to 20 instead of 200, however there is no save button to actually update the batch size to 20, meaning it just stays on 200. Can anyone help / has anyone else had this? (screenshot attached). I have tried downloading and reinstalling it but there is still no save button, even when I scroll to the bottom.