We have both A2k and A2k3 on some of our  PCs. You may have to completely
uninstall Office 2k3, then reinstall Office/Access 2k, then reinstall Office
2k3. The 2k3 install should detect the earlier version and ask if you want
to upgrade or keep. Not sure if the 2k3 install defaults this way or if you
have to enter it, but we made sure 2k3 components install to

C:\Program Files\Microsoft Office\OFFICE11

and 2k install is in

C:\Program Files\Microsoft Office\Office

Nothing's ever guaranteed with MS installs, but it works for us. Worst case,
uninstall everything, reinstall Office 2k3, and call Microsoft. :D