[BioC] Error: read.affybatch

[S Peri]

Hello group, 
 I am trying to read my cel files using read.affybatch
method.

I stored all my cel files, probe information file and
experiment file in one directory. 

I used the following commands:

>fls = list.files()
>ab = read.affybatch(filenames=fls)
Error in initialize(value, ...) : Is
breastCancerData_2.txt really a CEL file? tried
reading as text, gzipped text and binary
In addition: Warning message: 
Incompatible phenoData object. Created a new one.
 in: read.affybatch(filenames = fls) 


I am getting the above error.  What could be
happening. 
I am trying to analyze Mike West and Nievens Breast
cancer affy data (Duke University). 

Could any one please help me what is wrong here and
also how does a phenoData file look like. What is
phenoData. 

Please help. 

thank you

SP