Archana,

Which part is breaking exactly?  Is it breaking when it tries to read the
file or breaking when it tries to write to the file?  

From the information provided, I agree with Marc.  It sounds like some piece
of the data in the csv file might have a comma in it causing your columns to
be off.  It might be a good idea to write something that will count the
commas in each line and output it to you so you can check for the error line.

Otherwise, I have found that it is usually safer to use tab delimited files
rather than comma delimited files.  The reasoning for this is that it is
usually more likely to have table data with commas in it than table data with
tabs in it.  

If you think your data may contain commas or tabs, it is even safer to use
excel files, but it will require more effort and the use of Visual Studio
Tools for Office.