Red X on Mapped Drive on Reboot

I have 2 different configurations with the same problem.
The first is a Win XP Pro networked with a Win XP Pro.
The second is a Win XP Pro networked with a Win 2000.
On both configurations the Win XP pro has mapped drives.
When I reboot the XP system the mapped drives appear with
a red X on them. I open my computer and double click on
the network drive and it opens with no problem and the
red x goes away and everything is ok until the next
reboot. If I do not go into my computer and click on the
drive to reconnect it I cannot access from inside my
program.
When I mapped the drives I chose to reconnect a logon.
I have disconnected and reconnected the drives with no
change.

Joel