Doesn't work on my iPhone 4 w/iOS 4.2.1 – PortKnock Review

I have port knocking set up at home and I was looking forward to being able to knock from my iPhone. I downloaded this app (PortKnock v2.01) and it will not allow me to enter a host to knock. When I try to enter a host, the field will flash blue but no keyboard ever comes up for me to enter data. My assumption is that this app needs an update in order to work with iOS 4.2.1. Until that time it's useless with an iPhone 4 running the latest version of iOS (4.2.1 as of this writing).
Review by T_W__ on PortKnock.