Don't use the puart config at all when registering your application create function.
NULL, // Don't configure the puart.
Indeed what was mentioned by arvinds above was correct. The actually problem I was also have in was related to user error -- I was using 1 based port instead of 0, so was trying to configure port 3, pin 0 instead of port2, pin 0.... I'm sure I won't be the only one to make this dumb mistake. Just something to look out for.