The Collaborative International Dictionary of English v.0.48:

Illiteracy \Il*lit"er*a*cy\, n.; pl. Illiteracies. [From
   Illiterate.]
   1. The state of being illiterate, or uneducated; lack of
      learning, or knowledge; ignorance; specifically, inability
      to read and write; as, the illiteracy shown by the last
      census.
      [1913 Webster]

   2. An instance of ignorance; a literary blunder.
      [1913 Webster]

            The many blunders and illiteracies of the first
            publishers of his [Shakespeare's] works. --Pope.
      [1913 Webster]

WordNet (r) 3.0 (2006):

illiteracy
    n 1: ignorance resulting from not reading
    2: an inability to read [syn: illiteracy, analphabetism]
       [ant: literacy]