all right, i got it solved. here is the thread i posted in stack overflow.
https://stackoverflow.com/q/14727900/850848

I am using a ssis 2005 to do some sftp tasks using winscp. I googled it a bit but couldn't make it work. I got this error: [Execute Process Task] Error: In Executing "C:\Program Files\WinSCP\WinSCP.exe" "-script=C:\Documents and Settings\nian_z\Desktop\temp\SSISMovingSOA\removeSOA8.txt" at "C:\Program Files\WinSCP", The process exit code was "1" while the expected was "0".

Here is my winscp script used:

option batch abort
option confirm off
#open sftp://user:password@server:22
#cd /m/vo/Cont/fileftp
get OrderOutbound*
close
exit

For above script, I even tired leaving only one statement at a time, but still got error.