need help please[HOpenGL]

hello ; I am learning to use to HOpenGL to complete an asignement for next week and I have some trouble ; I have found a tutorial on the internet ; in that tutorial it was an example of the Rubik's Cube ; anyway ; in that example it was used a function called matrixExcursion ; and when I try to run the example it sais that : " ERROR file:.\RubikFace.hs:9 - Undefined variable "matrixExcursion" " I don't know what to do ; please help ; I need to know immediatly how to fix this problem ; thanks for your time in reading this , and hope to hear from you soon ; I wish you all the best --------------------------------- How low will we go? Check out Yahoo! Messenger’s low PC-to-Phone call rates.