Task Scheduler Problem

I have a question on a W2k Server.

I’ve created a batch file that uses “Robocopy” to copy
over data files from one directory to another directory. I
then used the Task Scheduler to schedule this task to take
place at 8:00 pm. I use the renamed administrator account
to do this and the correct password.

It runs fine the first night, but the second night it
fails and says unable to complete. If I open the task up,
repoint to the batch command and select apply, then type
in theadmin password again, that night it will work, but
the next night it will not.

Any help with this would be appreciated.

Thanks