I'm making this match 3 game on AS 3.0 Flash CS4 and I'm having this error:

TypeError: Error #1010: A term is undefined and has no properties.
at monsterQ/getMatchHoriz()
at monsterQ/lookForMatches()
at monsterQ/setUpGrid()
at monsterQ/startMatchThree()
at monsterQ/startGame()
at homeClass/startGame()

I'm not quite sure what did means. Can anyone help me? Thanks in advanced.