[R] How to override coerion error in 'scan'

[Kittler, Richard]

I am using 'read.csv' in V2.0.1 to read in a CSV file with the
colClasses option and am getting an error from 'scan' when it encounters
a non-numeric value for a 'numeric' column, i.e. 

 > ds <- read.csv(in_file, nrows=irow, row.names=NULL,
colClasses=zclass, 
                     comment.char="")
  Error in scan(file = file, what = what, sep = sep, quote = quote, dec
= dec, :
     "scan" expected a real, got "03/15/200523:56:03"

Is there a way to override this and just have it convert those values to
NA? The dataset is large so I would prefer not to have to import the
columns as character and convert them to numeric afterward.  

--Rich

Richard Kittler 
AMD TDG
408-749-4099