IIS and winscp.com

I'm trying to get a file from server. im calling winscp.com from c# code using System.diagnostics.process every things work fine when i run with light weight webserver provided with vs2005 during development. but fails once published to IIS. I have granted all the permissions required,tried changing machine.config/impersonation..and all that , but still fails.i can see the command window poping up and closing but no command is executed and retruns exit value 2. any ideas here ??

Thanks

on further tweaking i found the following
on light webserver executes the commands fine.
on IIS
command prompt opens
searching for host..

NO HOST FOUND

its executing remaining commands