Scheduler works then quits. Wants password AGAIN--why??

I set up the scheduler to run a set of DOS commands. It works for a
while then quits saying that it has a "launch failure" and the
password is bad. The error value is Error Value: 2147943726

Now, if I re-enter my user name and password (the same one as last
time) as the user account (this is an administrative account), it
works again for a while. I have it set to run even if I am not logged
on and at the "highest" level.

Why does it run for about 1/2 to 3/4 of a week and then quit. So damn
madening. Seems like the Vista Security has a BUNCH of these really
screwed up problems.

microsoft.public.windows.vista.security