[BioC] Not Available / "Missing" Values

[Mohammad Esad-Djou]

Hello, 
I would like to produce a matrix of Affybatch Object:

library(affy)
data.raw <- ReadAffy(filenames="./R/ME_cel/Expt1_R1.CEL")
> concentrations <- matrix(as.numeric(sampleNames(data.raw)), 16, 1, byrow = TRUE)
Warning message: 
NAs introduced by coercion 

(Not Available / "Missing" Values)

How can I correct my errors?

Thanks,
Mohammad