Q:

Is there a word for the phrase "I don't know what I don't know"? 

In my current job, I'm constantly trying to figure out when the next thing I don't know that I don't know is going to bite me in the butt and cause me to have to rework my code.   I've been working on a certain project for nearly a year, and still find out things that people have neglected to tell me, or are just considered tribal knowledge and everyone assumes you just "know", or is buried in the code (that I have to replicate in another language).   It's not malicious, it's just how it is here, but it's incredibly frustrating. 
So far the closest word I've found that sort of describes this situation is agnotology (the study of culturally induced ignorance, coined in 1995), but that's not exactly it. 
What word adequately describes the situation where you don't know what you don't know? 

A:

You might try adapting Rumsfeld's "(un)known (un)known" approach, although you would be best served by depoliticizing it in this situation.  What you're dealing with are known unknowns, or certain bits of information that you know you do not know.