I had the same problem. It turned out that the list of files from the
master included duplicates. When the slave completes the download and
tries to move the files into the index it comes across a file that does
not exist because it has already been moved so it backs out the whole
operation.
I've been hitting my head against a wall all morning trying to figure
this out and haven't managed to get anywhere and wondered if anybody
here can help.
I have defined a field type
positionIncrementGap="100">
I have two fields
required="false" multiValued="true"/