I am a new comer to the microarray data analysis arena,

Im following a tutorial R/Bioconductor, CSC, March19-22 2007 Preprocessing
cDNA microarray data.
and i am using the GPR files that i got in my experiments in the place of
the tutorial file

everything goes smoothly untill i use the following command

*ma <- normalizeWithinArrays(rg,method="p")

*where i get the error message:
Error in switch(method, loess = { :
  printer layout information does not match M row dimension

My question is what is the M row dimension and how can i check the M row
dimension, I hope *rg$printer *command will give the details of the printer
layout and about the number of grid columns and rows along with the spot
location

Thanks in advance for your time.

MLR

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