generating the flatfiles from server getting error

Hi,

source file type is   .csv. I am using executeprocess task to download the source file..its thrown error by the executeprocesstassk and also  through command prompt. all arguments are sitting properly. I checked each and every arguments.

with the same executables i can downloaded  few of the flat files.

But for this only I am facing an issue.actually How i am getting an issue is.

for eg flat file having 5 headers. like procid,procname,proccast,procsale,updateddate.

while running the task/from cmd prompt it 'll work fine for procid,procname,proccast. i mean to say getting data. but not getting rest of the  2 fields.

output: procid,procname,proccast,procsale,updateddate      only hearders without data.

for some times it's throws an error below  if i'll take few of the fields like procid,procname,proccast,procsale.

Error: I cant seem to download the file, please check the filename and URL. Web
Exception Error:

System.Net.WebException: The remote server returned an error: (500) Internal Ser
ver Error.
   at System.Net.WebClient.File(Uri address, String fileName)
   at System.Net.WebClient.File(String address, String fileName)
   at Script.Program.Main(String[] args)

but when i checked individually all fields are having data & excution is success.

Hope for the quick solution.

Thanks