FW: Help with SSH from Server 2003 to Linux

Greetings,
 
I am attempting to set up a scheduled rsync to back up a Windows Server 2003
box to a Linux (Ubuntu) box.  I have installed and configured openSSH
(OpenSSH_3.8.1p1 on windows and OpenSSH_4.2P1 Debian-7ubuntu3.1) with RSA
key.  It works fine from a DOS command line (that is, it does not prompt for
a password).  When I create a Scheduled Task, it prompts for a password.  To
trouble shoot, I have created a simple script that just does ?SSH
user@linuxHost?.  Again, it works fine at the DOS command prompt (no prompt
for a password), but when set up as a scheduled task, it prompts for a
password. 
 
I have tested the RSA key from an XP Home laptop to the Linux box.  On the
XP laptop, the scheduled job works fine, so it seems to be unique to Windows
Server 2003.  
 
Any suggestions?
 
Thanks in advance for any help,
Leon