Mysqldump direct pipe to RDS instance - error 32 on write

I'm following the directions from this article pretty much verbatim - trying to copy data from one RDS instance to another.

http://ift.tt/1LO0zC2

But I am getting the following error within about 2 seconds of starting:

mysqldump: Got errno 32 on write

I know this is a a broken pipe error, but I don't know why it's happening. Anyone have any ideas to troubleshoot?