The Collaborative International Dictionary of English v.0.48:

Misinterpretation \Mis`in*ter"pre*ta"tion\, n.
   The act of interpreting erroneously; a mistaken
   interpretation.
   [1913 Webster]

WordNet (r) 3.0 (2006):

misinterpretation
    n 1: putting the wrong interpretation on; "his misinterpretation
         of the question caused his error"; "there was no mistaking
         her meaning" [syn: misinterpretation, misunderstanding,
         mistaking]